Fuel-Index Surcharge Audits: Match Freight Invoice Lines to Contract Formulas

Direct answer: Reconcile a fuel-index surcharge by matching the invoice line to the contract’s stated index, observation period, calculation method and shipment, then document any mismatch before closing the review. A diesel-cost news story does not establish how a particular carrier calculates a shipper’s surcharge. The shipper’s own agreement and invoice records are the evidence for that check.

What was reported

Supply Chain Dive reported on October 15, 2026, that wholesale food distributor UNFI is managing surging diesel costs by hedging and using an AI platform to optimize routes.

Orca analysis: what to check

The report describes UNFI’s approach to higher fuel costs. It does not say how UNFI’s carriers price fuel surcharges, identify a surcharge formula, or establish that a particular shipper’s invoice should change. The recommendations below are original operational advice for shippers, not claims about UNFI or an endorsement by the publisher. They focus on a specific finance control: verifying that an invoiced fuel-index surcharge follows the applicable contract terms for the shipment being billed.

Why fuel-index surcharges need a line-level check

A fuel-related invoice charge can be difficult to review if the invoice shows only a surcharge amount, while the contract describes a formula and an index observation period. A reviewer needs to connect those pieces. Checking only that a surcharge appears on the bill, or comparing it with the prior invoice, does not establish that the right method or period was used.

Start with the governing agreement for the shipment. Depending on the terms, it may identify an index series or source, a particular observation date or period, a base value, an adjustment factor, the freight amount to which the percentage applies, and rules such as rounding or limits. Do not assume these terms are universal. Use only the terms that apply to the relevant carrier, service and shipment, including any documented amendment and effective date.

The purpose is not to challenge a surcharge because fuel costs appear to have moved, nor to infer a carrier’s costs from a news report. It is to test whether the billed amount follows the agreed calculation and whether the shipment record supports applying it. Keep a clear distinction between a confirmed calculation mismatch, a missing document, and an item that matches the contract.

Seven-step fuel-index invoice audit checklist

1. Identify the invoice line and shipment. Capture the invoice number, invoice date, service date, carrier name, shipment or load ID, bill of lading number, origin, destination, billed service, and fuel-surcharge code. Match these fields to the tender, rate confirmation or other shipment authorization. Flag a missing shipment identifier, conflicting service date, or invoice line that cannot be tied to an authorized movement.
2. Find the applicable pricing terms. Retrieve the agreement, rate confirmation and amendments that cover the shipment. Check the carrier, service, lane or other scope stated in those records, plus the effective date and any end date shown. Confirm which document governs if terms conflict under your internal review process. An agreement that does not cover the service date or shipment scope is not a reliable basis for recalculating the line.
3. Record the formula inputs specified by the agreement. Note the contract-defined index source or series, observation date or period, base value, adjustment factor, trigger, and any stated floor, cap or rounding rule. Record the exact terms that apply; do not substitute a different index or assume a standard formula. If the agreement does not identify a needed input, classify that as a documentation question rather than filling the gap with an assumption.
4. Check the index period against shipment timing. Compare the contract-required observation period with the service date and the period shown or implied on the invoice. If a lag or reference month is defined, use that stated rule. Flag an index period that does not match the contractual timing, an unexplained change from the prior billing period, or a missing reference needed to reproduce the calculation.
5. Recalculate the charge from the documented base. Use the contracted method and its stated inputs to reproduce the surcharge percentage or amount. Verify the base amount to which the surcharge applies, the calculation sequence, and any applicable limits or rounding. Compare the result with the invoice’s billed fuel amount and record the arithmetic. If the invoice does not disclose enough information to reproduce the calculation, request the missing detail through the established process.
6. Check the underlying shipment records and other billed lines. Compare service date, shipment ID, carrier, origin and destination across the invoice, bill of lading, tender, rate confirmation, and available pickup or delivery records. Review the base freight line and other surcharge lines so that the fuel charge is not applied to an unapproved amount or repeated under another code. Flag duplicate fuel lines, a surcharge on a shipment with no matching authorization, or inconsistent shipment details.
7. Classify, assign and close the exception. Record the invoice line, shipment identifiers, applicable contract version, formula inputs, calculation, evidence reviewed, exception type, reviewer and owner. Separate a confirmed formula or amount mismatch from missing index evidence, missing contract terms, and a pending response. Retain the disposition and supporting records so another reviewer can reproduce the result; do not mark an unresolved documentation gap as a confirmed overcharge.

Make the exception workflow useful to finance and transportation

Use exception categories that point to the next evidence needed. Examples include wrong index series, incorrect observation period, incorrect surcharge base, calculation mismatch, duplicate line, contract scope unclear, and supporting record missing. These categories help reviewers distinguish a math issue from a contract or data question without treating every flagged amount as an error.

Assign ownership based on the record required. A transportation reviewer may be best placed to locate a tender or shipment record; a contract owner may need to confirm which amendment applies; and accounts payable may need the calculation and invoice-line details to route a payment question. These are suggested responsibilities, not assumptions about a company’s organization. Set an internal follow-up date, preserve carrier or internal responses, and record who approved the final disposition.

When an invoice contains multiple shipments or surcharge lines, keep the review at the affected line level. A mismatch on one shipment does not establish that all lines on the invoice are incorrect. Likewise, a correct calculation on one load does not validate charges with a different service date, contract version or index period. Link each decision to the evidence for that specific movement.

Operational takeaways

• Maintain a calculation record. Store the applicable contract version, index input, observation period, surcharge base and reproduced result with the invoice exception.
• Track effective dates. Make the terms and amendments used for each service date retrievable, rather than relying on a current rate record alone.
• Separate evidence gaps from confirmed errors. Report the amount as unresolved when an input or supporting record is missing; document a confirmed variance only when the terms and math support that conclusion.
• Review exceptions by cause and owner. A count of open items is more actionable when finance can see whether each needs a contract clarification, shipment record, calculation check or duplicate review.

For CFOs, the control output should show how each reviewed surcharge was tested and whether it matched the applicable terms, remains open for evidence, or has a documented discrepancy. Transportation teams support that result by linking shipment records to the right pricing terms and retaining relevant amendments. This approach keeps fuel-index invoice review grounded in a reproducible calculation, not assumptions drawn from broader news about fuel costs.

Sources and further reading

• How UNFI tackles higher fuel prices (2026-10-15)

Explore more Orca freight audit resources.