The $420k lesson every contracts manager needs to hear
How a discrepancy between a draft and executed AS4902 D&C contract went undetected — and what it means for your governance process.
In construction contracts, the gap between a draft and an executed document is where risk lives. Not in the clauses themselves — but in the assumption that because a contract has been signed, the version that was signed is the version everyone is working from.
What happened
On a D&C project in regional Western Australia, a Provisional Costs Sum item was amended between the draft and the final executed AS4902 contract. The change was a $420,000 reduction in the PC Sum allowance for a specialist subcontract package. The amendment was made late in the negotiation process, noted in correspondence, but never reconciled against the project budget or the subcontract procurement schedule.
By the time the discrepancy was identified — during a routine contract review midway through construction — the subcontractor had already been engaged at the original PC Sum value, committed costs had been incurred, and the principal's approval for the overage was required. The commercial exposure was significant. The relationship damage was worse.
Why it happens
Document version control in construction is an informal discipline. Contracts are negotiated across email chains, redlined in Word documents, and finalised in PDF. The executed version sits in a folder. The working version lives in someone's head. When the two diverge, nobody notices until it matters.
What governance actually looks like
A governance system doesn't prevent negotiations from being messy. But it does create a register where document versions are tracked, discrepancies between versions are flagged, and the executed contract is the single source of truth that everything else is measured against. That's what 4wards.ai does — and why we built the platform around this specific failure mode.