Test a milestone payment schedule by placing every expected customer receipt and delivery cash outflow on a dated forecast, then comparing the largest cumulative cash deficit plus the required reserve with funding available on those dates. Trace each receipt back to its contractual trigger, acceptance evidence, invoice requirements and payment rule. The work product is a milestone-to-cash schedule and a funding decision showing the base case, delayed cases, funding conditions and approval owner. A positive contract contribution does not establish that payroll or supplier invoices can be paid when due.
The price covers the estimated work, and the payment percentages add to 100. But the supplier pays for equipment before testing, pays staff during the acceptance review, and cannot invoice the largest milestone until the buyer signs off. The bid model puts income in the month of completion. When approval moves, spending continues and the available credit is exhausted before the receipt arrives. The missing calculation concerns the sequence of cash, not the total selling price.
Follow the money to the bank account. Keep the contractual due date separate from the forecast receipt date, and keep both separate from accounting revenue. Start with the reviewed contract and delivery estimate; this is a funding test, not a substitute for general contract review or a margin sensitivity exercise. The cases, company names, dates, amounts and reserve limits below are fictional teaching examples. Sources were checked on 5 September 2026. Legal and financing terms require qualified review for the actual jurisdiction and contract; no example authorizes borrowing, changing an offer or delaying a supplier payment.
Payment basis
Write down what earns each payment
A row called “installation, 40%” is insufficient for a funding decision. Find the clause defining installation, the inspection procedure, the required certificate and the invoice route. Determine whether all sites must pass together or whether each site can earn a separate payment. Record the amount and the price base to which the percentage applies. Options, provisional sums and taxes may have different treatment from the core contract price.
Distinguish a payment for accepted work from an advance or other contract financing. Those mechanisms can have different security, recovery and approval conditions. Under the applicable US FAR 32.1004 framework, performance-based financing requires defined, verifiable events, distinguishes independent from cumulative events and provides for liquidation against delivery payments. Do not copy that mechanism into an unrelated services contract or assume that a task labelled a milestone automatically qualifies.
Where a stage depends on earlier stages, show the dependency explicitly. Equipment may pass its factory test while a required design approval remains unresolved. If the contract makes both prerequisites for payment, the factory certificate alone cannot support the forecast receipt. Equally, do not delay an independent, payable stage just because another stage is late. The model should reproduce the actual entitlement rather than the team’s general impression of progress.
Create one record for each payment right, not one record for every planning task. Include the controlling document and version, amount, trigger, prerequisites, evidence, approver, invoice route, deductions and unresolved interpretation. If the buyer’s schedule is mandatory, model it unchanged first. A bidder-preferred replacement is a separate proposal requiring a permitted route; it cannot silently become the assumed basis of the submitted price.
| Payment type | Evidence to inspect | Cash treatment |
|---|---|---|
| Accepted deliverable | Scope, acceptance criteria and certificate | Receipt follows the actual invoice and payment rules |
| Advance or contract financing | Eligibility, security, draw and recovery provisions | Cash received early is reconciled to later deductions |
| Cumulative milestone | All stated predecessor events | Move the receipt when a required predecessor moves |
| Retention release | Amount withheld and contractual release condition | Carry the balance until its separate release and payment |
| Optional work | Valid exercise or order and payment basis | Exclude uncommitted optional receipts from core funding |
Receipt timing
Keep acceptance, invoicing and payment on separate dates
Build the sequence from planned completion to evidence submission, review, acceptance, invoice eligibility, invoice receipt and cash receipt. Some steps may coincide or may not apply. Do not impose an acceptance step where the actual payment right does not require one. For every applicable interval, record the contractual rule separately from the planning assumption. A five-day internal allowance for preparing a certificate is a forecast input, not an extension of the buyer’s legal payment period.
The UK Cabinet Office’s current invoicing guidance distinguishes invoice receipt under the Procurement Act from the older starting point tied to verification. It also addresses invalid or disputed invoices and excluded contracts. The operational lesson is to check the applicable regime before using “30 days after approval” in a model. Record a reviewed due date; do not treat an administrative payment run as permission to override it.
For French public contracts, Articles R2192-12 and R2192-13 connect the starting point to receipt of the payment request, subject to specified exceptions, including uncertain receipt or a request preceding performance. German BGB §271a also needs its scope read carefully: subsection 5 excludes agreements on instalments and part payments from subsections 1 to 3. Neither reference supplies a universal milestone payment clock. Have the appropriate reviewer resolve the rule for the actual payment type.
Preserve the evidence that supports the date: acknowledgement from the required invoice system, acceptance record, approved amount and any timely dispute notice. The forecast can allow for late cash without surrendering the legal right to timely payment. Keep that delay as a stress assumption with an owner and escalation route. Do not add anticipated late-payment interest to available funding before its collection has a defensible basis.
Outgoing cash
Use payment dates, not the cost allocation curve
Ask the delivery team when purchases must be committed and finance when money must leave the account. A component used in March may require a deposit in January. Staff costs may accrue continuously but leave cash on a payroll date. A subcontractor may invoice independently of the customer’s acceptance. Enter each actual payment obligation with its supporting quote, agreement or payroll assumption. Do not assume that a buyer delay gives a right to defer an otherwise due supplier payment.
Reconcile the cash forecast with the estimate rather than copying every cost row as an outflow. Depreciation and allocated overhead are not necessarily new project cash payments on their accounting dates. Equipment purchases and refundable deposits can consume cash before their accounting effect. Show these differences in a bridge finance can review. A cash model that simply omits tax, insurance, shared operating obligations or warranty costs has not established full funding.
List available funding by source and date. For a facility, inspect commitment status, undrawn amount, conditions to draw, permitted purpose, security, covenants and maturity. Reduce availability for amounts already allocated elsewhere. A bank’s indicative offer does not cover a payroll date. Neither does an undrawn line whose borrowing base depends on an accepted invoice that the delayed milestone has not yet produced.
Keep restricted cash outside spendable availability. A guarantee may require cash collateral or consume the same credit capacity intended for working capital. Its fee is an expense; refundable collateral is a liquidity restriction, with a separate release date. Tax receipts also need their payment and recovery dates. Show gross bank movements and tax settlements in the live model rather than treating VAT collected from the buyer as permanent project funding.
| Input | Required distinction | Reviewer |
|---|---|---|
| Supplier deposit | Order commitment versus bank payment date | Procurement and finance |
| Staff cost | Accrual versus payroll and related remittances | Finance |
| Guarantee | Fee versus restricted cash or facility capacity | Treasury |
| Credit line | Nominal limit versus drawable dated availability | Treasury |
| Tax | Invoice tax versus collection, remittance and recovery | Tax reviewer |
| Retention | Contract price versus cash currently collectable | Commercial and finance |
Worked example
A £120,000 contribution can still need £280,000 of funding
Fictional supplier Brookmere bids £600,000 for a staged delivery. The simplified example has £480,000 of delivery cash costs, all expensed within the illustrated project, leaving £120,000 before financing and tax. There are no other cost-to-cash differences in this teaching case. The forecast excludes VAT, tax and financing charges to isolate payment timing; an actual approval must add them. The company has £80,000 of allocated unrestricted cash and a £220,000 committed facility drawable throughout the required period. A further £20,000 must remain as its approved liquidity reserve.
Expected receipts in 2027 are £120,000 on 26 February, £240,000 on 30 April, £180,000 on 30 June and £60,000 on 30 September. These are 20%, 40%, 30% and 10% of the price. The last amount is the case’s contractual retention release, not a general procurement requirement. The dates are explicit forecast assumptions after the relevant evidence, acceptance and invoice process, not examples of statutory deadline arithmetic.
Delivery outflows are £90,000 on 15 January, £50,000 on 29 January, £70,000 on 15 February, £100,000 on 15 March, £90,000 on 15 April, £50,000 on 15 May and £30,000 on 15 June. Immediately after the April outflow, cumulative spending is £400,000 while receipts are only £120,000. The £280,000 deficit is the funding peak. Add the £20,000 reserve: the requirement is £300,000, exactly the stated availability, with no spare capacity above that reserve.
By 30 April, the second receipt reduces the cumulative deficit to £40,000. A month-end-only forecast would show that smaller number and miss the £280,000 need earlier in the month. Calculate at every material cash date and determine the ordering of large same-day movements; do not assume a customer receipt will clear before a supplier debit. Retain a monthly summary for reporting, but base the funding approval on the dated low point.
| Date in 2027 | Delivery outflow | Customer receipt | Cumulative receipts less outflows |
|---|---|---|---|
| 15 January | 90 | 0 | -90 |
| 29 January | 50 | 0 | -140 |
| 15 February | 70 | 0 | -210 |
| 26 February | 0 | 120 | -90 |
| 15 March | 100 | 0 | -190 |
| 15 April | 90 | 0 | -280 |
| 30 April | 0 | 240 | -40 |
| 15 May | 50 | 0 | -90 |
| 15 June | 30 | 0 | -120 |
| 30 June | 0 | 180 | 60 |
| 30 September | 0 | 60 | 120 |
Delay test
Move the receipt and leave committed payments where they fall
Brookmere’s second stage requires an integrated test using a buyer-provided connection. In the base plan, the evidence is accepted on 12 April and invoicing follows. Test a scenario in which that dependency is unavailable, acceptance moves to 12 May and the £240,000 receipt moves from 30 April to 31 May. These are scenario dates, not a finding that a particular party is legally responsible or entitled to relief. Keep the April and May spending commitments unchanged unless a separately supported change exists.
After the £50,000 outflow on 15 May, spending has reached £450,000 but receipts remain £120,000. The peak deficit is now £330,000. The reserve raises the required funding to £350,000, leaving a £50,000 shortfall against the available £300,000. The month still ends with a much better position after collection. That later recovery cannot pay an earlier obligation.
Add a supported combined case: £12,000 of retesting cost leaves the account on 20 May before the delayed receipt. The deficit reaches £342,000 and the requirement including reserve becomes £362,000. The funding gap is £62,000. Delivery contribution is still £108,000 before financing and tax, or 18% of the selling price. This shows why a positive margin test and an adequate funding test need separate approval conclusions.
Propagate dependencies, not a blanket delay across every row. In this case, the planner confirms the June stage can still finish and be paid as forecast; the independent September retention condition is unchanged. If that evidence were absent, a second case would move the affected later receipts as well. Record the recovery work and its capacity basis. A spreadsheet that leaves later dates untouched merely to preserve a passing result is not a delivery forecast.
| Case | Peak cash deficit | Required with 20 reserve | Gap versus 300 available |
|---|---|---|---|
| Base schedule | 280 on 15 April | 300 | 0 |
| Second receipt delayed to 31 May | 330 on 15 May | 350 | 50 |
| Same delay plus retesting | 342 on 20 May | 362 | 62 |
Funding options
Close the shortfall with an executable change
A proposed earlier milestone helps only if the tender permits it, the event is meaningful and the evidence can be produced in time. Splitting a large acceptance stage into independently verifiable deliveries may reduce concentration, but a bidder cannot invent partial acceptance rights. Show the issued schedule and the permitted alternative side by side. Recalculate any price or evaluation effect and obtain approval before putting the proposal into the buyer-facing documents.
An advance also needs its full cash cycle. If £60,000 is paid early and £60,000 is recovered from a later payment, total consideration has not increased. Model the early receipt, the later deduction, any guarantee fee and the collateral or facility capacity the guarantee consumes. An advance arriving after the first supplier deposit does not solve that deposit. Check recovery again after variations so the same amount is neither omitted nor deducted twice.
Funding can instead come from a confirmed internal allocation or an approved facility increase. Brookmere would need at least £62,000 more usable capacity for the combined case before considering the extra financing and tax effects. The facility must be available by the actual draw dates and remain available until repayment is supported. An internal sign-off to seek finance is not a lender commitment. Do not count the same liquidity against another bid that may be awarded at the same time.
Supplier payment changes require agreement and legal review; withholding a due payment is not a cash-management assumption. Invoice financing also requires a financeable receivable, eligibility, permitted assignment and review of fees and recourse. If acceptance is the missing prerequisite, a facility against accepted invoices may not bridge the period before acceptance. Select the option whose conditions fit the failing dates, then rerun the entire forecast rather than subtracting a headline amount from the gap.
Approval record
Give finance a dated decision, not a reassuring total
The approval packet should contain the controlling payment and acceptance terms, the delivery cash calendar, the milestone-to-cash records, the base and stress results, and evidence of funding availability. State the lowest cash position, date, reserve, funding gap, facility maturity and unresolved dependencies. Include a bridge to the approved price model so finance can see financing charges, taxes and accounting differences that the teaching example deliberately leaves outside its arithmetic.
Ask delivery to confirm that the events can be achieved and evidenced. Ask finance to confirm the cash sources, reserve and repayment plan. Contract reviewers determine the legal payment and change position; the authorized bid approver decides whether the residual exposure is acceptable. A bid coordinator can prepare the model and flag missing evidence but cannot commit a credit facility or accept a new contractual condition on behalf of those owners.
Use a conditional decision only when the condition has an owner, evidence requirement and deadline before the relevant commitment. For Brookmere, “finance to arrange funding” is incomplete. The decision must identify the capacity required, when it must be drawable and what happens if confirmation does not arrive before bid release or another authorized commitment point. A failure should return the bid for a permitted redesign, escalation or no-bid decision, not disappear into an assumptions footnote.
After award, hand the approved schedule to delivery, accounts receivable and treasury. Track evidence readiness before the invoice date, compare actual receipts and outflows with the forecast, and rerun the funding test when acceptance, scope, retention or facility conditions change. Preserve the original approved case for comparison. The useful output is a payment plan the company can fund and operate, with an early warning before the next shortfall.
What good looks like
Useful outcomes from milestone payment cash flow in a tender
- Every expected receipt has a traceable payment trigger and supporting evidence.
- The forecast identifies the lowest cash position, its date and the required reserve.
- Acceptance delay and rework are tested against dated, usable funding.
- Advances, retentions, taxes and guarantees are not counted as free additional revenue.
- Finance can approve, condition or stop the bid using a reproducible funding decision.
Operating model
How to run the work
- 01
Read the payment mechanism
Collect the issued payment schedule, acceptance criteria, invoice instructions, contract definitions and amendments. Identify whether each amount is earned consideration, financing, retention release or another payment type.
- 02
Trace each receipt
Connect delivery, evidence, review, acceptance, invoice eligibility, valid receipt and the applicable payment rule. Assign responsibility for each dependency and distinguish due dates from forecast cash dates.
- 03
Date the outgoing cash
Use payroll dates, supplier deposits, delivery balances, tax payments and other cash commitments. Separate allocated accounting costs from actual additional payments and reconcile both views.
- 04
Find the funding peak
Calculate cumulative receipts less outflows at each material date, including within the month. Add the approved liquidity reserve and compare the requirement with funding usable at that time.
- 05
Test a missed acceptance
Move the affected receipts, propagate dependent milestones and add supported rework or holding costs. Do not delay supplier payments merely because the buyer has not paid.
- 06
Approve the funded position
Record the funding source, draw conditions, maturity, cost, reserve and escalation date. Obtain finance and delivery approval before a permitted payment proposal or bid is released.
Evaluation
Questions that change the decision
- What must happen before this particular sum can be requested?
- Can a completed stage be paid independently of later stages?
- Which evidence starts the payment clock under the applicable rules?
- How much cash is needed immediately before the next large receipt?
- Is the proposed facility committed, drawable and available for the full shortfall?
- What permitted change or funding approval closes a failing case?
Failure modes
Where teams lose control
Completion is entered as a cash receipt before acceptance and invoicing.
A positive month-end balance conceals a mid-month funding deficit.
A delayed common prerequisite blocks several supposedly separate payments.
An advance is counted again when its recovery is deducted from later invoices.
Restricted collateral or a conditional credit line is treated as spendable cash.
An unapproved change to mandatory payment terms is used to make the bid pass.
Measurement
Measure the finished job
Measure the completed workflow, including review effort and exceptions. Output volume on its own is not evidence of a better process.
- Peak cumulative delivery cash deficit and date
- Funding requirement including the approved cash reserve
- Drawable headroom at each material payment date
- Days between planned completion and expected cash receipt
- Value of receipts dependent on the same acceptance event
- Unfunded amount in each approved delay scenario
Questions
Common questions
Does a profitable tender automatically have enough cash to deliver?
No. Profit compares income and cost under an accounting basis; funding depends on when receipts and payments occur. Brookmere’s base example leaves £120,000 before financing and tax but reaches a £280,000 delivery cash deficit before the April receipt. Review the dated deficit and required reserve alongside the contribution.
Should the payment forecast start at milestone completion?
Start by tracing the actual payment entitlement. Completion may precede evidence review, acceptance and a valid invoice, or the contract may use a different financing mechanism. Enter those steps separately where they apply. Keep the legally reviewed due date distinct from a later receipt assumed for a stress test.
Is a monthly cash-flow forecast enough?
Not when large receipts and outflows fall on different dates within the month. Calculate the position at each material movement, including the order of same-day transactions where it matters. A monthly report can summarize the result but should not hide the funding peak used for approval.
Can a bidder propose earlier milestone payments?
Only through the route the procurement permits. Determine whether the schedule is mandatory and whether alternatives can be proposed and evaluated. Describe objective evidence for the earlier payment and recalculate the commercial effect. Do not make an unapproved alternative the hidden assumption behind a compliant-looking price.
How should an advance and retention be treated?
Enter the advance on its supported receipt date and its recovery as deductions from the appropriate later payments. Enter retention release separately using its contractual conditions. Reconcile total customer cash with the agreed price and adjustments. Include guarantee fees and restricted collateral where applicable.
Can an available credit limit close the funding gap?
Only the amount that can actually be drawn on the required dates counts. Check commitment, draw conditions, existing allocations, security, covenants and maturity. A receivables facility may be unavailable before the invoice becomes eligible. Finance must approve the funding and its cost, not just record a nominal limit.
What should stop approval of the payment schedule?
Stop when a material payment trigger is unresolved, required cash exceeds confirmed availability, funding depends on an unapproved contract change, or the model excludes material obligations. Record the failing date and amount, assign the decision to the responsible authority and resolve it before the relevant bid or delivery commitment.
Sources
Primary references
- FAR 32.1004: events, amounts and liquidation of performance-based financing Acquisition.gov
- Procurement Act guidance: electronic invoicing and payment Cabinet Office
- Code de la commande publique: payment-clock provisions, R2192-12 to R2192-15 Légifrance
- BGB §271a: scope and exceptions for payment and acceptance periods Gesetze im Internet
About the author
Tony Kim
Tony writes about applied AI, dependable product engineering and the systems that turn complex response work into controlled delivery.
Zelius
Managed tender intelligence and bid execution for teams that want the commercial outcome.
Suppliers, founders and commercial teams pursuing public or private opportunities. Start with the workflow, constraints and evidence you already have.
