How is the amount due calculated?
An interim certificate values everything done to date, then pays only the difference from the last certificate. The figures below are illustrative; the retention rate and recovery terms always come from the subcontract.
| Line | Amount |
|---|---|
| Work measured to date | SAR 1,200,000 |
| Approved variations to date | SAR 80,000 |
| Gross valuation | SAR 1,280,000 |
| Less retention at 5% | − SAR 64,000 |
| Less advance payment recovery | − SAR 50,000 |
| Less amounts previously certified | − SAR 900,000 |
| Net amount due this period | SAR 266,000 |
The arithmetic is simple. The arguments are never about the arithmetic. They are about whether each line is right.
Where should each figure come from?
Every line on a certificate has an owner somewhere else in the project. A certificate prepared in a spreadsheet copies those figures; a certificate prepared in the ERP reads them.
| Line | Where it comes from | What goes wrong when it is copied |
|---|---|---|
| Measured work | Site quantities and inspections | Claimed quantities accepted without evidence |
| Approved variations | Authorised change decisions | Unapproved work paid, or approved work missed |
| Retention | Subcontract terms | Wrong rate, or a release missed at completion |
| Advance payment recovery | Subcontract terms and payment history | Recovered too fast, too slow or not at all |
| Previously certified | The certificate history | An amount paid twice |
| Contra-charges | Notices and back-charge records | A deduction without notice, and a dispute |
Why do payment certificates cause so many disputes?
Because the evidence for one certificate is spread across the site diary, the quantity surveyor's measurement sheet, the subcontract file, the variation register and the accounts system. When the subcontractor challenges a figure, the main contractor has to rebuild the reasoning from five places, and the subcontractor is doing the same from their own copies.
A certificate that links each line to its source does not end disagreements. It moves them from "where did this number come from?" to "is this measurement right?", which is a much shorter conversation.
What changes when certificates sit in the same ERP as the rest of the project?
The certificate stops being a document assembled at month end and becomes a step in the chain.
- Upstream: the subcontract package comes from the same tender, award and procurement records, so its scope and rates are the ones that were approved.
- On site: measured work, inspections and subcontract package progress are recorded once, and the certificate reads them.
- Commercial control: variations, notices, retention, recoveries and payment conditions stay linked to authorised commercial decisions.
- Downstream: the approved certificate updates committed cost, reaches the finance ledger and moves the cash expectation, without being typed again.
The same measured work also supports the main contractor's own claim to the client, so the margin on each package is visible as it is earned. That is the full chain Crolle is designed to cover as one ERP: tender, estimation, award, planning, procurement, subcontracts, cost, revenue, finance, cash, closeout and documents. How the budget behind a package is set is covered in how a tender estimate becomes cost control.
Common questions
What is retention in a subcontractor payment certificate?
Retention is a percentage of the gross valuation that the main contractor holds back as security for the subcontractor completing the work and correcting defects. The rate and the release points are set in the subcontract, commonly with part released at completion and the rest after the defects period. Tracking it against the subcontract is what stops a release being missed or paid twice.
What is the difference between an interim and a final payment certificate?
An interim certificate values work done to date during the subcontract and pays the difference from the last certificate. The final certificate settles the whole subcontract account after completion, including the final measurement, all variations, the release of retention and any outstanding deductions. The final certificate is only as good as the interim records behind it.
Can a subcontractor be certified for a variation that has not been approved?
That depends on the subcontract terms, but as a rule a variation is certified once it has been instructed and valued under the contract's change procedure. Keeping instructions, notices and approvals in the same system as the certificate is what lets a quantity surveyor see at once which variations are approved, which are pending and which were never instructed.
Can the AI agent in Crolle approve a payment certificate?
No. The agent can prepare a draft certificate from measured work, approved variations and the subcontract terms, and show the evidence behind each figure. An authorised person reviews and approves it. Delegated authority, human approval and an audit trail apply to every certificate, as they do to every other commercial decision in Crolle.
Crolle is opening early access to a small group of contractors and partners. To see it on your own projects, write to info@crolle.ai.