Freight Billing Post-audit

What the post-audit is

Carriers overcharge more often than most companies see: a rate above the contract, a missed discount, a fuel surcharge above the table, an accessorial the contract does not allow, a bill paid twice. The post-audit looks back at the bills your company already paid, finds those overcharges and asks each carrier, in writing and in your company’s name, to refund or credit them.

The sample post-audit — what it finds on nine paid bills

Sample Shipper Inc.’s nine bills, each paid in full, audited afterwards exactly as yours are: every overpayment and every double payment becomes a written claim with its clocks; one is already refunded, with ZetaVolt’s share taken out.

• EXF-220131 paid $391, owed back $10

  Liftgate billed $85.00; the contract says $75.00.

• EXF-220118 paid $360, owed back $360

  Paid twice — the second payment is owed back in full.

• EXF-220140 paid $645, owed back $105

  Discount billed $975.00 on $1,500.00; the contract gives 72% ($1,080.00).

See the sample post-audit

Bills paid twice — recovered in full

A shipment paid twice is one of the costliest mistakes in freight: the whole second payment is money your company is owed back, and it often goes unnoticed — the same bill paid again, the same shipment paid under a new invoice number, a corrected bill paid with the first.

• How ZetaVolt finds it: every paid bill you bring in is matched by carrier and shipment number (the PRO) — or the invoice number when there is no PRO — against every other paid bill you brought in. A payment above the bill’s own total is found too.
• What happens: a written duplicate-payment claim in your company’s name asks the carrier for the whole second payment back, as a refund or a credit to your company, with its deadlines.
• What it recovers: the whole second payment. For example, a $1,200 shipment paid twice → $1,200 owed back to your company; ZetaVolt’s share at 45% is $540, and your company keeps $660.

How it works

1. Sign up your business and sign the Freight Post-Audit Agreement (a minute, with your billing ZIP code for invoices).
2. Bring in your contracts and tariffs, then the bills you already paid, with the date each was paid.
3. Each bill is checked against the contract in force on its ship date: rates, discount, minimum, fuel, every accessorial, the class, and anything paid twice.
4. Every overcharge becomes a written claim with your company as the payee, with its deadlines.
5. You send it from your own mailbox in one tap, or ZetaVolt sends it for you in your company’s name and follows up.
6. The carrier refunds or credits your company. The recovery is recorded, and ZetaVolt’s share is billed.

How your company gets paid

Every claim asks the carrier to pay your company directly: a refund check, a credit memo, a credit on a later bill or statement, or an offset against what you owe it. The money never passes through ZetaVolt. ZetaVolt never receives, holds or moves carrier money, and a carrier payment sent to ZetaVolt by mistake is returned to the carrier.

How ZetaVolt gets paid

ZetaVolt’s share is 45% of what the carriers actually refund or credit your company — and nothing else. Bringing in bills, the audit and every claim cost nothing; when nothing comes back, nothing is owed. A share under $1,000 is charged to your card on file when you have one with ZetaVolt; otherwise, and always from $1,000, it comes as an invoice from Paddle, our reseller, due in 15 days and paid by bank transfer (wire or ACH) or card.

For example: a claim the carrier pays $2,000 on → ZetaVolt’s share is $900; a claim the carrier declines → $0.

How a recovery is recorded

• You mark the claim recovered, with the check, credit memo or statement.
• Zeta spots the carrier’s credit on a later bill or statement and asks you to confirm it.
• The carrier answers through the claim’s own link that it paid or credited, and you confirm it.

A recovery Zeta or the carrier reports counts after 15 days without an answer, as the agreement says; one recorded wrongly is corrected and its share refunded within 30 days.

How far back

By federal law a shipper generally has 180 days from receiving a motor carrier’s bill to contest it in writing, and 18 months to sue for an overcharge; your contract may set a shorter window. Every claim shows its own dates. Bills older than that can still be claimed as goodwill, which the carrier may decline.

What we can audit, and what we cannot

Electronic freight bills you already paid, with the date each was paid, read and audited by ZetaVolt’s own software:

• EDI freight invoices. X12 210 (truck), 110 (air), 310 (ocean) and 410 (rail), from your carriers or your EDI provider — uploaded, sent to your own ZetaVolt address, or picked up from your EDI mailbox (SFTP or AS2).
• Carrier billing data files. CSV or Excel files of invoices exported from a carrier’s billing portal, your TMS or your accounts payable system.
• Bills sent by your own systems. JSON sent by your TMS or ERP to your own ZetaVolt address, as bills are made.
• PDF invoices made by a carrier’s billing system. Electronic PDFs with the words in them (the kind a carrier emails), one bill per file.

Not audited: paper bills, scans, photos and faxes — ZetaVolt does not key bills in by hand.

Bringing in paid bills costs nothing: ZetaVolt is paid only its share of what carriers refund or credit you. A file or bill ZetaVolt cannot read is refused.

Each bill is checked line by line against the contracts, tariffs and fuel tables you bring in: the rate, the discount, the minimum, the fuel surcharge, every accessorial, the freight class and duplicates. You get what to approve, what to hold back and why, the written notice for the carrier, and the report your accounts payable pays from.

How your paid bills come in

• Upload the paid bills — an EDI file, your accounts payable export, a carrier portal’s CSV or Excel file, or a PDF from the carrier’s billing system — or paste them in.
• From your systems: the paid-invoice export of your TMS, ERP or accounts payable system (Oracle, SAP, MercuryGate, Manhattan, Blue Yonder, Descartes, e2open, Kuebix and others), and the invoice files of UPS, FedEx and the LTL carriers’ portals.
• The date each was paid comes from the file, or you give one date for the whole file.

What a look back at paid bills can hold

Industry estimates, not a guarantee. Your results depend on your carriers, contracts and bills.

• About 4.5% of LTL freight bills had a billing error — 11,881 errors in nearly 250,000 LTL invoices audited.

  Source: AFS Logistics, “Stat’s Incredible: Common LTL Invoicing Errors” · published undated · read 2026-10-29

• 42.8% · 14.4% · 12.3% · 10.3% of those errors were accessorial charges, fuel surcharges, freight class, and the discount, minimum or rate.

  Source: AFS Logistics, “Stat’s Incredible: Common LTL Invoicing Errors” · published undated · read 2026-10-29

What can still be claimed depends on the clocks: a bill contested in writing within 180 days of receipt (49 U.S.C. § 13710), an overcharge suit within 18 months (§ 14705), and your contract’s own window when it is shorter. Older bills are goodwill — the carrier may decline.

ZetaVolt will publish its own clients’ results here once there are case studies.

Sign up for the post-audit

Your business’s account, then the Freight Post-Audit Agreement (only about the post-audit), then bring in your paid bills. No card is needed to start: ZetaVolt is paid only when money comes back.