How should I assess a subcontractor's application?

Assess it the way you wish your own applications were assessed: from evidence, with reasons, on time. Value the works against the subcontract's pricing document from what the site actually shows, the walk, the progress records, the delivery tickets, rather than starting from the application and knocking a percentage off, which is indefensible in both directions: it overpays what is not there and undercuts what is. Where your number differs, state the reason line by line: not certified, not complete, no evidence of the materials, plus the calculation. Reasons are not a courtesy; they make your assessment an assessment rather than an arbitrary discount, and they are what a Pay Less Notice needs anyway if the difference hardens. Then operate the machinery: the Payment Notice inside its window saying what you will pay and its basis, and, where you intend to pay less than a Notified Sum, the Pay Less Notice by its own deadline with the figures behind it. Under the Act an application you fail to answer in time can become payable in full, right or wrong, which turns notice administration into the cheapest risk management a main contractor does. The assessment that is fair, evidenced and on time survives adjudication, keeps a good subcontractor solvent mid-job, and costs the least over the life of the account.

Picture a small main contractor with nine subcontracts, where assessments happen late on Friday by feel: most applications shaved a standard tenth, notices sent when someone remembers. It works until the groundworker, squeezed elsewhere, takes advice. One shaved application was never answered with a Payment Notice or Pay Less Notice inside the windows, so the Notified Sum is simply due; a seven-day letter arrives, and adjudication is mentioned. Paying it in full, including the plant time the site knows was double-counted, costs more than the proper deduction ever would have, because the deduction was never made lawful. The rebuilt routine is not elaborate: each account's windows mapped from its own subcontract, assessments from the site diary and tickets with reasons on every line, notices prepared with the assessment and issued inside the windows, everything filed per account. Two subcontractors grumble the new numbers are tighter than the old shave; both get shown the workings; neither takes it further, because there is nothing procedural left to attack.