To resolve an invoice price discrepancy, establish the applicable commercial terms, compare equivalent quantities and price units, and send the supplier a line-level correction request. Keep the issue open until the corrected document or credit is verified and finance confirms the required next step.
A difference is a question to investigate. It might be an overcharge, an approved price change, a missing discount, or a unit conversion. Starting with an accusation makes the straightforward cases harder and the ambiguous ones slower.
Download the invoice price investigation worksheet (Excel) to work through a live invoice.
Assemble the document chain before contacting the supplier
Collect the invoice and its line references, the PO revision actually issued, the supplier's acknowledgement, and the contract, price schedule, or accepted quote supporting the price. Include approved amendments and relevant correspondence. Record the document dates and the period each price covers.
Do not assume the newest attachment governs every delivery. A new price might apply to orders placed after a date, shipments after a date, or a named batch. If the documents conflict, ask the authorised commercial owner to determine which terms apply before requesting a correction.
Receiving records help establish which goods the invoice covers. For a partial shipment, identify the invoiced quantity and corresponding receipt rather than calculating against the entire PO. Keep uncertainty visible: “Receipt allocation not yet confirmed” is more useful than a precise-looking estimate built on the wrong quantity.
Compare the same thing on both sides
Check these fields before calling the price wrong:
- Supplier item and internal material number, including revision or grade.
- Currency, price unit, order unit, and any documented conversion.
- Quantity covered by this invoice, including previous partial invoices.
- Agreed discounts, freight, surcharges, and their application basis.
- Effective dates and approved changes to the commercial terms.
A price per hundred pieces is not comparable with a price per piece until converted. A surcharge included in the quoted unit price must not also be added as a separate charge. Conversely, a separately agreed charge should not be mistaken for an increase in the material price.
Keep taxes outside the procurement variance calculation unless finance provides the basis. State exactly what your calculation includes. This prevents a supplier from disputing a mixed total when only the base material price is at issue.
Calculate a reproducible difference
For a simple base-price discrepancy, use:
Potential price difference =
(invoiced unit price − applicable agreed unit price)
× affected invoiced quantity
This is an investigation amount until the underlying terms and quantity are verified. It is not a recovered amount.
Illustrative example: an invoice covers 800 machined brackets at $12.40 each. The approved schedule for those orders specifies $12.10. The PO has the older $12.40 price, while the supplier's acknowledgement refers to the new schedule. The potential base-price difference is $240: 800 × $0.30. Freight is separately agreed and excluded from this comparison.
The invoice may match the PO despite the discrepancy with the applicable schedule. Microsoft's invoice matching documentation describes configurable comparisons between invoices, POs, and receipts. That matching result is useful evidence; the applicable agreement still needs to be established when the PO is questioned.
Send one request the supplier can answer
Use a short message with references and a specific requested outcome:
Subject: Price review — invoice [number], PO [number], line [line]
The invoice shows [quantity] [unit] at [price/currency].
Our applicable [schedule/quote and revision] shows [price/currency].
The base-price difference is [amount]; [charges] are excluded.
Attached: invoice line, issued PO, and relevant agreed price evidence.
Please confirm the applicable price and, if agreed, provide the
corrected invoice or credit reference and expected issue date.
If you use different terms, please send the supporting revision.
Choose a response date appropriate to the invoice timetable and your supplier relationship. Make the deadline explicit internally, with a named owner. Finance decides any payment hold, release, or application of a credit; the buyer supplies the evidence and tracks the supplier response.
Work the reply through to closure
If the supplier agrees, capture the amount, affected lines, document they will issue, and promised date. “We will look into it” is an acknowledgement, not agreement. “Credit approved” is progress, not proof that the credit was issued or applied.
If the supplier disputes the request, isolate the disagreement. Are they using a different effective date, material revision, quantity, or accepted amendment? Ask for the missing evidence and route a commercial interpretation to the buyer. Do not repeatedly send the same original request.
On receipt of a corrected invoice or credit, compare its references and amount with the agreed resolution. Check whether only some lines were corrected. Keep the remaining balance open with its own next action. Link finance's confirmation of the financial treatment so a colleague can distinguish supplier resolution from settlement.
Handle mixed causes without mixing the calculation
An invoice can contain a genuine price discrepancy and a valid extra charge. Split the work by the fact being tested. Ask the commercial owner to establish the applicable price, logistics to supply the approval for an expedite, and receiving to reconcile any quantity uncertainty. One disputed total should not obscure which part is already supported.
Consider an illustrative invoice for 600 parts at $8.50 each, plus $150 freight. The applicable price is $8.20, and an approved email separately permits the $150 freight. The price difference is 600 × $0.30 = $180. The invoice's material amount is $5,100; the expected material amount is $4,920. Including the valid freight, the corresponding totals are $5,250 and $5,070. The correction remains $180, not $330.
If the freight approval is missing, mark the $150 as a separate open question. Do not automatically add it to the supported price request. Finance may need to decide how the unresolved charge affects processing, while procurement continues the price correction independently.
If the supplier corrects the invoice by changing quantity instead of price, stop and reconcile the document. Removing units to reach the desired total can leave receiving and inventory records inconsistent. Ask for a correction that preserves the factual quantity and identifies the actual price adjustment.
Resolve partial invoices and earlier credits explicitly
Calculate against the affected invoiced quantity, then deduct only verified prior corrections covering the same issue. Do not deduct every credit from that supplier; it might relate to a return, another order, or a rebate.
For an illustrative order of 1,000 units, the first invoice covers 400 and the second covers 600. Both use $5.30 where the verified applicable price is $5.10. The first difference is $80, and the second is $120. A previous $50 credit explicitly allocated to the first invoice leaves $30 on that invoice and $120 on the second: a $150 remaining request.
Keep the original $200 difference, the earlier $50 correction, and the $150 outstanding amount separate. This lets finance reconcile the full history while the supplier receives a request only for the remaining balance. If the $50 credit cannot be allocated confidently, record that uncertainty before submitting another claim against the same lines.
A corrected invoice that replaces an earlier version also needs a clear relationship. Retain both versions and ask finance which document is valid for processing. Procurement should not delete the earlier record or assume that a revised attachment automatically reverses a posted transaction.
Decide when the issue belongs with an internal owner
If the supplier's price is supported and the PO is stale, the next action may be an internal correction rather than a supplier claim. If a new agreement is not yet accepted, the buyer must resolve the commercial position. If the invoice references the wrong receipt, receiving must establish the allocation. Name the owner who can supply the missing fact.
Escalate a decision with a short choice: accept the supported price, request a specified correction, obtain missing evidence, or approve a commercial resolution. Include the amount, source, uncertainty, and deadline. Avoid sending a long email chain with a vague request for approval.
Check whether the process is improving
Measure supported price issues closed during a defined period against issues entering that workflow, while also reporting the open backlog and its age. A busy month can produce more closures without reducing the backlog. Separate closure reasons: corrected document, verified credit, invoice valid, unsupported claim withdrawn, or commercial resolution.
For financial reporting, report potential differences investigated, supplier-accepted corrections, and finance-verified outcomes separately. Do not add successive stages of one amount. For process quality, review the share of submitted price requests later withdrawn because of wrong units, dates, or missing amendments. That is a useful internal error measure only if the denominator and review period are stated; it is not a universal false-positive benchmark.
Prevent the same discrepancy on the next order
Identify why the wrong price reached the document chain. It may be an outdated price record, an unprocessed amendment, or a supplier using a different effective-date rule. Assign the correction to the person authorised to change that record, with the supporting agreement attached.
Use the invoice discrepancy resolution checklist for the handoffs between purchasing, receiving, and finance. Mandel's invoice discrepancy workflow follows this operational work from investigation through supplier correction, bringing commercial decisions to the people who own them.
