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Answers · Machine shops

Customer Changed the Drawing Mid-Job: Who Pays, and How the Office Makes Sure Someone Does

When a customer changed the drawing mid-job, who pays for the change comes down to what the shop and the customer agreed about the new revision, in writing, before the parts shipped — and when nobody re-prices it, the shop pays by default, because the invoice goes out at the old price. The floor side — stop, lay the two prints side by side, decide — is well covered elsewhere. This guide covers the office side that decides the money: what the UCC and, on government work, the Changes clause say, the three places the revision has to match, a ten-minute re-price check, a count of closed jobs, and when to call a contracts attorney instead.

By , founder of Lumina Business Advisory · Updated · Sources checked · Editorial standards

Who pays when the customer changes the drawing mid-job

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Answer it in the Self-Audit

There are only three ways a revision ends, and two of them are fine. The customer pays: a revised quote goes out, the buyer issues a PO revision at the new price or lead time, and the invoice matches it. The shop absorbs it on purpose: the change is small, the customer is worth keeping, and somebody decides to eat the cost and writes that decision down. Or the shop absorbs it by default: the new print reaches the floor, the floor builds what the print says, and nobody asks whether the price still covers it until the invoice has gone out at the old number.

Only the third is a leak, and nobody sees it, because no one decided anything. The floor built the print, the estimator never heard about the revision, and the office invoiced what the PO said. Every person was right, and the shop still paid for the tighter tolerance and the second setup.

So the useful version of “who pays?” is not a legal question first. It is whether anyone is assigned to ask it, every time a new revision arrives, before the cost is spent.

What the paper says: the PO, the quote and the UCC

Where a PO for parts is a sale of goods, it runs under Article 2 of the Uniform Commercial Code as the shop’s state has adopted it; whether a given job counts as goods is itself a question for the shop’s attorney. Three lines of the model text matter here. They are quoted below, not interpreted; how they apply to one PO in one state is the attorney’s call.

  • Modification. UCC § 2-209(1): “An agreement modifying a contract within this Article needs no consideration to be binding.”
  • Written-change clauses. UCC § 2-209(2): “A signed agreement which excludes modification or rescission except by a signed writing cannot be otherwise modified or rescinded,” and § 2-209(4) adds that an attempt at modification that does not meet that requirement “can operate as a waiver.”
  • The quote against the PO. UCC § 2-207(2): additional terms in an acceptance “are to be construed as proposals for addition to the contract. Between merchants such terms become part of the contract unless” the offer expressly limits acceptance to its terms, they materially alter it, or notification of objection has been or is given within a reasonable time.

The practical reading for the office — an operating lesson, not a legal conclusion — is that the paperwork that exists when the parts ship is what both sides will argue from. A quote that says “price valid for Rev B only,” a PO that names a revision, an email that accepts Rev C with no word about price: each one is evidence, and the shop controls only its own. Whether an emailed Rev C plus an unchanged PO price amounts to an agreed change at the old price is an attorney’s question; the operational fix is to make sure it never has to be asked.

On government work: the 30-day window

On a fixed-price federal supply contract, the Changes clause is FAR 52.243-1, Changes — Fixed-Price (Aug 1987). Paragraph (a)(1) lets the contracting officer, by written order, change “Drawings, designs, or specifications when the supplies to be furnished are to be specially manufactured for the Government in accordance with the drawings, designs, or specifications.” Paragraph (b) says that if the change increases or decreases the cost or time of performance, the contracting officer “shall make an equitable adjustment in the contract price, the delivery schedule, or both.” Paragraph (c) sets the clock: “The Contractor must assert its right to an adjustment under this clause within 30 days from the date of receipt of the written order.” The clause’s own instructions add that the 30-day period may be varied according to agency procedures, so read the number in the contract, not this summary.

Contracts for commercial products use a different clause. FAR 52.212-4(c) says: “Changes in the terms and conditions of this contract may be made only by written agreement of the parties.” And a shop that is a subcontractor, several tiers down from the government, gets its rights from the PO the prime or the next tier up wrote — which may flow some clauses down, add its own notice period, or both. The revision log below exists so that any of these windows can be met with a date, not a memory.

One caution on dates. The FAR is being rewritten under the Revolutionary FAR Overhaul, and agencies are issuing deviations part by part, Part 43 (Contract Modifications) among them. The text above is as published on acquisition.gov on October 17, 2026 (FAC 2026-01). The version that binds a shop is the one in its own contract; its contracts attorney can say which applies.

Three places the revision has to match: PO line, traveler, invoice

A revision is a fact that has to be recorded in three documents owned by three different people. When the three agree, the shop is paid for what it built. When they drift, the drift is where the money goes.

  • The PO line. The customer’s PO, or its latest revision, names the part number and the drawing revision, with the price and the delivery date for that revision. If the buyer sent Rev C by email and the PO still reads Rev B, the shop is building one thing and has been ordered to deliver another.
  • The traveler. The router or traveler on the floor names the revision being built. It changes when the floor gets the new print — often faster than anything else in the shop, because nobody wants to scrap a part.
  • The invoice. The invoice line names the part number, the revision and the price. It is usually built from the PO, which is why an un-revised PO sends out an invoice at the old price for the new part.

Three mismatches are worth naming. Traveler ahead of PO: the floor ran the new rev and the paper never caught up — the classic default absorb. PO ahead of traveler: the buyer revised the order and the floor is still cutting the old print, which is a scrap problem before it is a price problem. Invoice behind both: everything was right until billing copied a stale line.

The ten-minute re-price check on every incoming print

The fix is not a new system. It is a short check that runs every time a new revision lands, done by whoever quoted the part, recorded in one row of a revision log, and finished before the floor runs the change. It takes minutes when the change is trivial, and the minutes are the point: a trivial change gets recorded as trivial, and a real one gets a price.

  • What changed: dimensions and tolerances, added or removed features, material or finish, outside processing such as heat treat or plating, quantity, and inspection requirements such as a first article or added certs.
  • Where the job stands: not started, material cut, in process, or partly shipped — the same change costs very different amounts at each stage.
  • Price and lead-time effect: none, up or down, with a number and the setups or operations behind it.
  • The decision: re-quote, absorb on purpose (with the reason and who decided), or ask the customer before going on.
  • The paper trail: the date the revised quote went out, the date the customer acknowledged it, and the date the PO revision arrived.
  • The hold rule: the floor does not run the new revision until the row has a decision, unless the owner says otherwise in writing for that job.

Illustrative example: a 200-piece order quoted at $40 a part on Rev B. Rev C arrives after the first 50 are done, adding a thread and tightening one bore. The check takes ten minutes and says the change adds a second operation of about two minutes a part plus a new setup. The shop sends a revised quote, the buyer revises the PO, and the last 150 parts invoice at the new price. Without the check, the 150 parts ship at $40 and the extra operation is paid for out of margin. The numbers are hypothetical; the mechanism is not.

Count the closed jobs before changing anything

Before adding a log or a rule, find out whether the shop has this problem at all. The count takes an afternoon and needs nothing new: closed jobs, their PO revisions and their invoices.

Take the last 20 closed jobs that had a drawing revision after the PO was issued. For each one, note four things: whether a revised quote went out, whether a PO revision came back, whether the invoice carried the new revision and the new price, and — for those that did not — whether anyone decided to absorb the change or it simply happened. Then, for the default absorbs, estimate what the change cost from the job’s own setup and run times.

If all 20 were re-priced or knowingly absorbed, the shop does not need this guide. If a third were absorbed by default, the count is the business case, written in the shop’s own numbers. Either way, the answer is a fact rather than an impression.

When not to hire anyone — and when to call an attorney

Most of this needs no outside help. A shop that sees a mid-job revision a few times a year can run the check on one sheet. Where the owner quotes, programs and ships every job personally, the three documents live in one head, and a note on the traveler handles the risk.

Call the shop’s attorney rather than a consultant when there is a live dispute: a customer refusing to pay for a change it requested, a PO with a written-change clause the shop missed, a government order where the assertion window may have passed, or a battle-of-the-forms question about whose terms govern. We give no legal advice, and nothing here is a reading of any shop’s contract.

If revisions are one of several places money slips between the RFQ and the cleared payment — next to quotes nobody followed up, lot charges left off the quote and shipped jobs waiting on paperwork — that is where a machine shop consultant earns a fee, and it is what the Revenue Review counts. It takes two weeks, with read-only access to the shop’s own quote log, POs, travelers, shipping records and invoices; prints and customer IP stay where they are. It ends in a written report with a monthly dollar figure wherever the records support one and a ranked list of what to fix. We are not machinists, we do not run a shop, and there is no published machine-shop client on this site yet. The next step is a free 20-minute call that says plainly when the arithmetic does not justify the fee.

Before any next step

What should you do next?

Fix it yourselves.
If the cause is clear, it lives inside one process, and one person can own it — take the play from this page and run it. That outcome is fine with us; it is why the play is published in full.
Order one bounded build.
If the fix is known but needs configuration or integration inside your stack — a cadence wired into your own system, an alert, a handoff — scope that one build, with us or with anyone you trust. The six systems we build show what bounded looks like.
Start with the Review.
If the causes are debatable, the problem crosses departments or systems, or the economics are unclear — diagnose before anyone builds. The Revenue Review: $4,500 fixed, two weeks, computed from your own records. Read a sample finding before you decide — free, no email.

Asked right after

Who pays if the customer sent the wrong drawing?
It depends on what the PO, the quote and any written revision say, and on what the two sides agree once the error is found. Operationally, the shop’s position is strongest when it can show the revision it quoted, the revision on the PO and the date the corrected print arrived. Whether the customer owes for parts made to its own wrong print is a question for the shop’s attorney, and the paperwork is what the attorney will ask for first.
Can a customer change the drawing after the PO is issued?
A customer can send a new revision at any time; whether the shop must build it at the old price is a different question. Under UCC § 2-209(1), a modification of a contract for goods “needs no consideration to be binding,” which is one reason to answer every new revision in writing with its price and lead-time effect before running it. On a federal fixed-price supply contract, FAR 52.243-1 lets the contracting officer change drawings by written order, with an equitable adjustment.
How long does a contractor have to ask for an adjustment on a government drawing change?
Under FAR 52.243-1(c), the contractor “must assert its right to an adjustment under this clause within 30 days from the date of receipt of the written order,” though the clause notes the period may be varied by agency procedures. A subcontractor’s window is whatever its own PO says, which may be shorter. Read the contract, log the date each written change arrives, and ask a contracts attorney when a deadline is close.
Should the invoice show the drawing revision?
Yes, on every line where the part has one. When the invoice names the part number and the revision, a mismatch with the PO is visible before the invoice leaves, and the customer’s receiving and payables staff can match it to the right PO line without a phone call.
What if the floor already ran the new revision at the old price?
Record what happened, then decide on purpose. The shop can send a revised quote for the remaining quantity, ask for a price change on the parts already made, or absorb the change and write down why.

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