A finished drawing set doesn’t tell your finance team when cash will arrive. Before buying another collection tool, separate the wait to make work billable, the wait to send the invoice, and the wait for the client to pay. Each delay has a different owner, which means the same reminder won’t solve all three.
In our retail engineering engagement, the firm collected payment five days sooner on average, weighted by invoice value, in the following quarter. On its observed receivables, that meant $1.1M in cash arriving earlier. The firm had earlier access to money it was owed, without treating that money as new profit.
Our work connected project records, captured unpriced changes, checked drawings before review and helped managers act on budgets each week. The firm separately reported about $1.98M in annual retail margin improvement: $1.2M in annual priced and billed changes plus a $784K estimated annual benefit from less rework, calculated from the pilot reduction. The cash-timing result belongs beside that margin result, not inside its total.
You can apply the same habit of tracing work through to its business consequence to billing. The invoice timeline below gives your project manager and finance lead one record of where a milestone waited, what remains unpaid and who can move it next.
Start with the event that makes the fee billable
An invoice can be missing because finance hasn’t sent it. It can also be missing because the contract’s billing condition hasn’t been met. If those two situations share one “unbilled work” label, finance can spend the week chasing a project manager for evidence that the client hasn’t supplied yet.
Choose one fixed-fee billing milestone and find the fee authority, required deliverable or acceptance, and supporting documents. Record the actual completion and acceptance dates separately from the date every required billing input became available. That’s your invoice-ready date. Use the agreed terms for that milestone, because completion alone may not authorize billing.
Follow the milestone through internal approval, dispatch and the client’s receipt or portal acceptance, then through payments. Keep the project, milestone and invoice IDs joined. A project can have several invoices, and a payment can cover several invoices, so finance needs to allocate each receipt to the correct balance before the timeline can explain anything.
The scope-change method helps get extra work priced. The weekly cost-to-complete review helps protect delivery margin. This record starts from the authorized fee and asks where its path to cash slows down.
Find the seven days a payment reminder can't remove
Here’s what that looks like in practice. These are illustrative calendar-day records for a $100,000 milestone, with no tax, credits or retention. The client accepts the deliverable and all billing inputs are ready on day 1. The invoice waits for internal approval until day 8, goes out on day 9 and is paid in full on day 39, its agreed due date.
| Event | Worked record | What the wait means |
|---|---|---|
| Fee authority | Signed milestone for $100,000 | Finance has an agreed amount and billing condition. |
| Accepted deliverable and invoice-ready | Day 1 | Required evidence is complete. |
| Internal invoice approval | Day 8 | Seven calendar days waiting for approval. |
| Sent and accepted by client portal | Day 9 | One more day before the client receives a valid invoice. |
| Due and paid in full | Day 39 | Thirty days after sending, paid on time. |
| Owner and next action | Finance lead with the approving PM | Check why a complete invoice waited seven days. |
The ready-to-cash interval is 38 days: eight before sending and thirty afterward. A collection reminder can’t recover the seven days before approval because the client doesn’t yet have an invoice to pay. The finance lead should first check whether the approver lacked time, lacked authority, or had a real unresolved question. Only the first two point directly to changing the approval route.
If approval moved to day 2 and sending to day 3, payment would arrive on day 33 if the client still paid thirty days after receiving the valid invoice. That’s six days earlier in this example. A fixed client payment run could reduce or erase that gain, which is why you keep actual receipt dates instead of assuming every internal day saved becomes an earlier cash day.
This gives the finance lead a specific operating decision before committing to software. Its value to the firm depends on whether cash availability is what limits the next stage of growth.
If you’re an engineering firm leader and want to grow your firm without completed projects leaving your team chasing cash, we’ll identify the biggest bottleneck standing in your way, build the plan to remove it, and implement it in eight weeks* or less - guaranteed or we continue to work for free and you don’t pay.
Find my bottleneck* Eight-week delivery, or twelve weeks when substantial data foundations are required, as agreed before work begins. If a covered stage fails its agreed benchmarks, we provide up to four additional weeks of remedy work at no charge, then waive or refund that stage’s fee if it still fails. Successfully delivered stages remain payable. Agreed client-caused delays pause the clock. Delivery guarantee terms.
Keep partial payments and unpaid invoices in view
A paid-invoice average can look better simply because the slowest invoices haven’t been paid yet. Keep the unresolved balances beside the completed timing measure so that a change in which invoices closed doesn’t look like a better collection process.
For example, add a second invoice for $50,000, also sent on day 9 and due on day 39, but paid on day 19. Across these two fully paid invoices, the value-weighted sent-to-payment time is:
($100,000 × 30 days + $50,000 × 10 days) ÷ $150,000 = 23.3 days, rounded.
The larger invoice receives more weight because more cash waited for those thirty days. This is a defined paid-cohort measure, not a replacement for your firm’s full receivables reporting. Record the cohort’s invoice dates, client and contract mix, number of invoices and total value so the next comparison uses the same basis.
Now add a third invoice for $80,000, sent on day 9 and due on day 39. It receives $30,000 on day 29. At the day-49 review, the remaining $50,000 is still outstanding, forty days after sending and ten days overdue. Keep the receipt’s amount and date, but don’t call the whole invoice paid on day 29. This third invoice sits outside the two-invoice completed measure above and stays visible in the open-balance view.
When it eventually closes, calculate its payment timing from each receipt’s amount and elapsed days, then include it under the same stated cohort rule. A single “paid date” would hide the difference between early partial cash and the final balance. Record credits, write-offs and retention separately too. A balance can disappear through a credit without producing cash, and retention may have its own future release condition.
For an unpaid invoice, record the reason and next action. If the portal rejected missing evidence, the owner needs to correct the submission. If the client disputes a change fee, the project manager needs to resolve the commercial question. If a valid invoice is simply overdue, the collections owner can follow up. Calling all three “late payment” sends the wrong work to the same person.
Copy the record before adding automation
Use one record per billing milestone and linked invoice, with a repeatable receipt list. Split allocations where one invoice covers several milestones. Preserve the original events when an invoice is corrected, because replacing its first sent date would hide the rejection and resubmission delay.
| Field | Fill in for your invoice |
|---|---|
| Review cutoff and day basis | Date: ___ . Calendar days or working days: ___ . |
| Identity and fee authority | Project: ___ . Milestone: ___ . Invoice: ___ . Contract or approved change reference: ___ . |
| Amount and billing condition | Amount and currency: ___ . Tax, retention and credits shown separately: ___ . Condition and supporting records: ___ . |
| Work and readiness | Completed: ___ . Accepted, if required: ___ . All billing inputs ready: ___ . Missing input and owner: ___ . |
| Approval and issue | Submitted for internal approval: ___ . Approved: ___ . First sent: ___ . Client receipt or portal acceptance: ___ . |
| Terms and exceptions | Agreed due date: ___ . Dispute, rejection or credit amount, date and reason: ___ . Resubmission or resolution: ___ . |
| Each cash receipt | Receipt ID: ___ . Amount allocated to this invoice: ___ . Cash date: ___ . Repeat for every receipt. |
| Open position at cutoff | Unpaid balance: ___ . Age since first sending: ___ . Days past due, if any: ___ . Retention and disputed amounts: ___ . |
| Decision and follow-through | Current waiting reason: ___ . Evidence link: ___ . Accountable owner: ___ . Next action and date: ___ . |
The project manager owns the milestone evidence and commercial questions. Finance confirms the invoice, receipts and balance. Together they can calculate the gaps between events and identify whether a long wait was internal, contractual or with the client. Missing dates stay marked unknown until checked against the source.
Start with your existing billing system. Deltek’s billing guidance describes project setup, billing terms and supporting-document requirements. If those features already cover the gap, configuring them and assigning an owner may be enough. Buying another tool won’t give an approver time or settle a disputed fee.
If finding the evidence across email and project records is the slow step, a bounded AI assistant could draft this timeline. Give it permitted records and the firm’s event definitions. Require a source link for each proposed date, amount and waiting reason, with “unknown” for missing or conflicting evidence. Fixed calculations should handle elapsed days and balances, while the project manager and finance lead approve the facts and actions.
For the $100,000 example, the assistant’s draft would point to the day-1 readiness evidence and day-8 approval. It could propose an approval delay for review, but it shouldn’t infer the approver’s reason from elapsed time alone. Test it on records finance has already checked, including partial receipts, duplicate documents and rejected invoices. Measure wrong links, missing events and total checking effort. Keep it in draft use until the agreed checks pass, and leave invoice dispatch, fee changes and client messages with authorized staff.
Give the next delay an owner and a test
Take one recent group of comparable billing milestones, including unpaid ones, and build the timeline with the project manager and finance lead. Choose the first recurring delay they can change, then write down the owner, action and review date. In the worked example, that action is to establish why complete invoices wait for approval and test a supported change to that route.
Compare the next similar group using the same event definitions and cutoff rule. Check the approval gap, valid-invoice sending date, open balances and actual cash dates together. Keep client payment terms, disputed amounts and workload visible, because a different client mix or a waived fee could improve one number while making the business worse off.
The immediate reward is a decision your team can act on: who owns the wait, what they’ll change and how you’ll see whether cash actually arrives sooner. If earlier cash would let you fund the firm’s next growth goal, compare this opportunity with the other demands on your people, time and money. That wider choice starts with the goal you want to reach over the next 3–18 months.
If you’re an engineering firm leader and want to grow your firm without completed projects leaving your team chasing cash, we’ll identify the biggest bottleneck standing in your way, build the plan to remove it, and implement it in eight weeks* or less - guaranteed or we continue to work for free and you don’t pay.
Find my bottleneck* Eight-week delivery, or twelve weeks when substantial data foundations are required, as agreed before work begins. If a covered stage fails its agreed benchmarks, we provide up to four additional weeks of remedy work at no charge, then waive or refund that stage’s fee if it still fails. Successfully delivered stages remain payable. Agreed client-caused delays pause the clock. Delivery guarantee terms.