When a purchase order and a supplier proforma invoice do not match, you must move from confusion to a clear, auditable decision. The immediate goal is not to prove who is right but to define the controlling terms and create a record that supports the next commercial move. Use a standard working method so you can measure impact, reduce risk, and close the gap with a single documented exchange. This article gives a concrete step sequence you can run the same day a mismatch appears. Each step explains what to check, how to document what you find, and what to ask the supplier so your next action is supported by a visible record.

Step 1: Identify and date the controlling documents

Start by capturing the exact identifiers for both documents. Record the purchase order number, the proforma invoice number, and the issue dates. Note who issued each item and which department signed or approved it. If either document is labeled as a revision or amendment, save the full filename and any older versions so you can prove the sequence of changes.

If multiple purchase orders or multiple proforma invoices exist for the same goods, trace the chain to a single controlling document. If you cannot determine a clear sequence, treat this as a critical discrepancy and flag it for immediate clarification. A dated record of your identification step is the baseline for any later claims about which terms controlled the transaction.

Step 2: Compare every commercial and technical field line by line

Work item by item. For each SKU or line, compare description, part number, unit of measure, quantity, unit price, total price, and currency. Do not rely on short descriptions. If the product uses internal SKUs, match supplier part numbers and cross-reference with your product spec sheet. Note any tolerances, minimum order quantities, or allowed overrun percentages.

Next check terms that change commercial exposure. Compare incoterm and named port or place, lead time and acceptable delivery window, packaging and palletization requirements, and shipping method. Review payment terms, deposit requirements, financing references, and whether freight or insurance are included. Also check whether the PI lists additional fees such as handling, customs clearance estimates, or inspection costs that are not in the PO.

• SKU and description match
• Quantity and unit of measure
• Unit price, currency, and totals
• Incoterm, delivery point, and lead time
• Payment terms, deposit, and added fees
• Packaging, labeling, and inner carton counts

Step 3: Log discrepancies and assess impact

Create a discrepancy log with one line per mismatch. For each entry record: document fields compared, PO value, PI value, numeric delta, and a short impact note. Impacts should include cost change, timing change, minimum order implications, and fulfillment risk. Rank each mismatch as low, medium, or high impact so you and stakeholders can prioritize the response.

For price and quantity differences, calculate the dollar effect on the order total and on unit economics. For term differences such as incoterm or payment timing, estimate who absorbs additional cost or risk. Keep the log factual and numeric; avoid interpretation in this file beyond the impact note. That keeps the log usable for procurement, finance, or operations review and speeds approval for corrective action.

• Fields: PO/PI numbers, SKU, field compared
• Values: PO value, PI value, delta
• Impact: cost, timing, risk, approval need
• Priority: low, medium, high

Step 4: Send one clear correction request to the supplier

Compose a single email that references both the PO and the PI numbers and dates, attaches the discrepancy log, and lists each mismatch with the resolution you want. For each line include the exact text you expect on the corrected document: SKU, quantity, unit price and currency, incoterm and delivery point, and payment terms. Give the supplier a concrete deadline for a corrected PI or a signed amended PO.

State the next document you will accept. For example, either a revised PI that matches the existing PO or an amended PO that matches the PI. Request the supplier mark the corrected document with a new revision number and an authorized signatory name. Copy procurement, finance, and the relevant operations contact so the reply is visible and becomes part of your internal approval path. Save the outgoing email and any replies as part of the order record.

• Reference both document numbers and dates
• Attach the discrepancy log
• List desired corrections line by line
• Set a reply deadline and next acceptable document format
• Ask for supplier sign-off and revised revision number

Step 5: Decide, document, and close the loop

When the supplier responds, update your discrepancy log with their proposed fixes and the new document identifiers. If the supplier accepts your corrections, save the revised PI or amended PO as the controlling document and circulate a short internal approval note that names that document. If the supplier counters, record the counteroffer and the commercial impact so approvers can decide whether to accept, reject, or renegotiate.

If changes materially affect price, timing, or risk, route the revised terms through finance or an authorized approver before releasing funds or confirming production. Where you cannot reach agreement quickly, pause any commitment actions such as deposits or shipment instructions until a controlling document is signed. Keep every exchange attached to the order folder so a future audit or dispute shows exactly who agreed to what and when.

Create a line-by-line discrepancy log now and email the supplier one correction request referencing both document numbers.