Resources
Freight audit guides for shippers
Published May 29, 2026 · Plain-English notes from Rob Eller and the Eller Audit team.
Every guide on this site is written to answer one specific question a freight buyer asked us — no fluff, one number, one clause, one Monday-morning action. Browse the catalogue below or start with the head freight audit page.
Start here — what an audit actually does
If you've never run a freight audit before, start with the head guide. The two buyer-side pages help you evaluate the people and tools that do the work.
Freight Audit: A Plain-English Guide for Shippers Who Pay the Bills
PillarThe 7 errors a real audit catches, what your contract should say, and how much you should expect to recover.
How to Choose a Freight Audit Company (and What Most Get Wrong)
Buyer guidePerformance vs. subscription, scope, contract-clause expertise, and the 5 red flags to walk away from.
Freight Audit Software: Buyer's Guide for Mid-Market Shippers
Buyer guideWhat software catches (mechanical errors) vs. what still needs a human (interpretive disputes). When each fits.
Freight Audit and Payment (FAP): What It Is and What to Ask
Buyer guideWhat an FAP provider does, how they charge, who holds your cash between invoice and carrier, and the three clauses to demand.
Freight Billing Errors: 9 Overcharges and the 180-Day Clock
GuideThe nine errors that recur on every mode, how duplicate bills happen, and the 49 USC 13710 dispute window.
Parcel audit — UPS and FedEx
Parcel invoices have the highest mechanical-error rate of any freight category. These guides cover the four biggest recovery levers.
Parcel Audit: How UPS and FedEx Overcharge (and How to Catch It)
PillarThe 9 overcharge categories worth auditing and what each typically recovers as a % of parcel spend.
UPS Late Delivery Refund: How to Claim What You're Owed
ClusterWhich UPS services are guaranteed, the 15-day claim window, and the refund math line by line.
FedEx Money-Back Guarantee (GSR): The Refund Most Shippers Forget
ClusterHow the GSR works, what FedEx actually pays back, and the 15-day claim window that kills most claims.
Delivery Area Surcharge (DAS): The Map UPS and FedEx Won't Show You
ClusterThe 5 DAS categories, the quarterly ZIP list, and the worked dollar math on a 30,000-package account.
Fuel surcharges and accessorials
Mechanical line items that compound across every shipment. Worked-dollar examples and dispute language inside.
Fuel Surcharge: How It's Calculated and How to Audit It
HubThe EIA index, the table, and the base across LTL, truckload, parcel and rail, and the six places the math breaks.
Dimensional Weight: How It's Calculated and How to Audit It
CalculatorThe dim weight formula, the 139 vs 166 divisor, a calculator, and the dimension adjustments that raise parcel bills.
Accessorial Charges: What They Should Cost and How to Audit Them
PillarThe 9 accessorials carriers bill most often, their typical dollar ranges, and the contract clauses that cap them.
FedEx Fuel Surcharge: How to Audit the Math Line by Line
ClusterHow FedEx pegs the surcharge to the DOE diesel index and where the math goes wrong week to week.
UPS Fuel Surcharge: Reading Your Contract vs the Invoice
ClusterUPS's three separate surcharge tables (Air, Ground, Freight) and the 5 failure modes that cost real money.
Detention and Demurrage: What Carriers Can Actually Bill For
ClusterFree-time rules, the evidence carriers must produce, and how to dispute a charge with the receiver's yard log.
LTL shipping
How less-than-truckload freight is priced, from tariff to invoice, and how to audit it.
LTL Shipping: How It's Priced and Where the Bill Goes Wrong
GuideThe six layers of an LTL rate, a quoted-vs-billed worked example, and why most of the gap is the shipper's own inputs.
LTL Freight Audit: A Plain-English Guide for LTL Shippers
PillarThe line-by-line method for LTL invoices: class, FAK, fuel cap, minimum charge, and accessorial evidence.
Carrier contracts
The clauses that decide every invoice. The headline rate isn't the negotiation.
Operational documents
The paper trail that wins disputes six months later. Get these right at the dock and audits get easier.
Bill of Lading (BOL): The Legal Document That Governs Your Shipment
PillarThe three roles a BOL plays, the fields that decide disputes, and the language to pre-print on your template.
Proof of Delivery (POD): What Makes It Valid for a Dispute
ClusterThe fields that make a POD dispute-ready and how a missing OS&D check can cost a $4,200 claim.
Freight Class: How to Read the Code on Your Bill
PillarHow NMFC class is determined, why a one-class reclassification raises bills 15-25%, and the FAK alternative.
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