Amazon remeasures products, reclassifies size tiers, and adjusts fulfilment fees without sending a per-ASIN notification. The higher fee applies to every order from that moment forward — silently eroding your margins until the monthly P&L review surfaces the damage. SentryKit monitors FBA fee rates on every tracked ASIN in real-time and fires the instant a fee changes, so you can recalculate, reprice, or dispute before weeks of impact compound.
A fee increase requires immediate unit economics review. A fee restoration after a successful dispute means reclaiming margin that was silently taken — and confirming the fix held.
Amazon has changed the FBA fee on a tracked ASIN — whether through a scheduled fee update, a dimensional reclassification after warehouse remeasurement, or a category surcharge adjustment. Every order from this moment forward costs more to fulfil. The alert fires in real-time with the old rate, new rate, and which fee component changed.
Amazon has corrected the fee on a tracked ASIN — either because a measurement dispute was successful, a category policy was reversed, or a surcharge expired. The per-unit cost is back at the previous rate. SentryKit confirms the restoration so you can update your margin calculations and close the action item.
No vague "fee rates may have changed" notice. SentryKit shows you the old rate, the new rate, which component changed, and the monthly P&L impact — so you know what you're dealing with immediately.
The first question is always: is this disputable? The answer determines whether you fight it or adjust to it.
SentryKit's alert will show you which fee component changed. If it was a size tier or weight reclassification after Amazon remeasured your product, compare the new tier against your actual product and packaging dimensions. A reclassification into a higher tier than your actual measurements warrant is disputable — and if successful, restores the original fee retroactively.
Go to Seller Central → Manage Inventory and locate the ASIN. Use the FBA Revenue Calculator to verify the current fee tier or contact Seller Support to initiate a measurement dispute. Provide your actual product dimensions and packaging specifications. Amazon will remeasure the item at the fulfilment centre and correct the fee if the dispute is upheld.
Whether or not the change is disputable, recalculate your ASIN-level margin immediately using the new fee. Determine the monthly P&L impact (fee increase × average monthly unit volume) and whether your current selling price still produces acceptable margin. This calculation is what determines the urgency of the next action.
If the fee increase is accurate, your options are: increase the selling price (accounting for Buy Box competitiveness), renegotiate COGS with your supplier, or redesign packaging to reduce dimensions or weight to qualify for a lower fee tier. Check Account Health to confirm there are no related performance flags on the ASIN during this period.
Amazon's fee schedule announcements cover the broad changes. They don't tell you when your specific ASIN was remeasured and reclassified into a different tier. SentryKit monitors the actual fee on each tracked ASIN individually — catching the silent per-product changes that schedule monitoring misses.
A successful measurement dispute requires knowing exactly when the reclassification happened and what changed. SentryKit's alert includes the previous fee, new fee, changed component, and timestamp — giving you everything you need to file a dispute immediately, before more orders are processed at the wrong rate.
Every fee change is logged with full detail. This history supports annual planning, sourcing decisions, packaging redesigns, and dispute documentation. You have a complete fee timeline for every product in your catalogue — not just the current rate.
| Capability | SentryKit | Manual Monitoring |
|---|---|---|
| Detects per-ASIN fee change | ✓ Real-time | ✗ Only via monthly P&L reconciliation |
| Catches dimensional reclassifications | ✓ Same alert regardless of cause | ✗ Invisible until manually checked per ASIN |
| Identifies which fee component changed | ✓ Component, old rate, new rate, timestamp | ✗ Not available without manual comparison |
| Dispute-ready documentation | ✓ Full event log per ASIN | ✗ Nothing retained automatically |
| Monitors all ASINs simultaneously | ✓ Entire catalogue, always on | ✗ One ASIN at a time, manually |
| Covers mid-year silent changes | ✓ Continuous monitoring year-round | ✗ Only checked after annual announcement |
"Amazon remeasured one of my products and bumped it up a size tier. I had no idea until SentryKit fired the alert. Filed a dispute the same day, won it, and got a retroactive refund. That paid for months of SentryKit."
"I used to find fee changes when I couldn't figure out why margins were shrinking. Now I find out immediately and either dispute it or adjust my price the same week. Completely different situation."
"The fee history log is underrated. When I do quarterly margin reviews, I can see exactly which ASINs had fee changes and when — and whether we've recouped the cost through repricing or disputes."
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