FBA Fee Overcharges: How One Bad Remeasurement Can Cost You Thousands a Year

Your FBA fulfillment fee is set by your product's size tier— a bucket determined by its measured dimensions and weight. You provide measurements when you list, but Amazon doesn't take your word for it: warehouse scanning systems (Cubiscan machines) periodically re-measure units as they move through fulfillment centers, and whatever the machine says becomes your fee.

Machines measure squashed poly bags, dented boxes, and units with a shipping label doubling the height of an envelope. A product that measures 0.2″ over a tier boundary doesn't get a warning — it gets a new, higher fee on every unit you ship from that day forward, with no notification.

The math that makes this expensive

Fee-tier boundaries are cliffs, not slopes. Crossing from standard to oversize, or up a weight band, commonly moves the per-unit fulfillment fee by anywhere from £0.30 to several pounds. The damage compounds with velocity:

A £0.75/unit overcharge on a product selling 400 units a month is £3,600 a year — from a single measurement error on a single SKU.

And because nothing announces the change, sellers typically discover it months later (if ever), usually while investigating why a profitable product's margin quietly shrank.

How to detect a bad remeasurement

1. Watch the fee, not the listing. The FBA Fee Preview / Estimated Feesreport shows the fulfillment fee and recorded dimensions per SKU. Snapshot it regularly; a fee that moved when your packaging didn't is your signal.
2. Compare recorded dimensions to your spec.The report shows the dimensions Amazon is billing on. If your box is 16.5″ and Amazon's record says 18.1″, that's not your product — that's their scan.
3. Check the tier, not just the fee — annual fee-card updates also move fees. A rate-card change affects everyone; a remeasurement changes your recorded dimensions. Only the second is disputable.

Getting it fixed — and getting the money back

1. Open a case in Seller Central requesting a remeasurementof the ASIN. Include the manufacturer's spec sheet or your own photographed measurements against a ruler.
2. When the remeasure corrects the dimensions, request reimbursement of the fee difference for every unit shipped at the wrong fee. Amazon honors these within a limited dispute window — roughly 90 days from the fee change — so speed matters far more than sellers expect.
3. Keep shipping. The overcharge accrues per unit, so the dispute amount grows while you wait — but the claim window doesn't.

The watchdog approach

The reason this leak persists across the industry is simple: nobody opens the fee report weekly for every SKU. It's watchdog work — perfect for software, tedious for humans. Clawback's Fee Watchsnapshots every SKU's recorded dimensions and fulfillment fee on every sync, flags the moment a measurement changes, computes the overcharge across the units you actually shipped, and generates the remeasurement request with the before/after evidence table filled in. Connect your account and the first pass covers your whole catalog.

Related reading: how to read the inventory ledger and the 2025 reimbursement policy change.