Every fixed-price project eventually meets a moment where something was not quite what either side assumed. How that moment is handled tells you more about a vendor than the proposal ever did.

01. The two ways this usually goes wrong

Silent scope creep. The vendor absorbs small changes without discussion, the project quietly grows, and eventually either quality or the timeline suffers without anyone having agreed to that trade-off explicitly.

Surprise invoicing. The vendor treats any deviation from the original brief as billable, and the client discovers a change was “extra” only when the invoice arrives — after the work is already done and there is no real leverage to negotiate.

Both failure modes come from the same root cause: no agreed process for what happens when scope needs to move.

02. What we do instead

Changes of scope, delays on the client’s side, and third-party changes underneath the project all go through the same written process: agreed, priced and scheduled before the work is done, not after. Nothing reaches an invoice that was not agreed to first, in writing, at a specific price.

This sits inside the sequence described on How It Works: the design is signed off before anything is built, and any change to it after that point runs through this same written process rather than being absorbed silently or billed retroactively.

03. What we absorb versus what goes through change control

Not every deviation is the client’s to pay for. If we underestimated the work — misjudged complexity, missed a requirement that was reasonably discoverable during the Diagnostic — that overrun is ours to absorb. That is a direct consequence of measuring before quoting rather than guessing: if we have done the measurement properly, an overrun caused by our own estimation is our responsibility, not yours.

What goes through change control is different in kind: scope that genuinely was not part of the original agreement, delays caused by the client’s own availability, or a third-party system changing underneath the build in a way nobody could have planned for. These are real costs, but they are not ours to absorb quietly, and they are not yours to discover after the fact either.

04. Why this matters for margin, not just for trust

Unmanaged scope creep is one of the specific mechanisms behind margin eroding even as project volume grows — work expanding quietly beyond what was priced, on both sides of a vendor relationship. Written change control is not just a fairness mechanism between us and a client; it is the discipline that keeps a fixed-price engagement fixed, for both sides, instead of drifting.

05. What this looks like in practice

A change is raised. It is priced and scheduled in writing before anyone starts on it. Only once that is agreed does it become part of the work — and only then does it become part of the invoice. That sequence, repeated consistently, is what “no surprises” actually means in practice, rather than as a phrase in a proposal.

See the full payment structure and what triggers written change control — what each engagement covers →