A fee estimate and a charged transaction answer different questions. Use the estimate to understand expected costs, then use actual charges to investigate a possible discrepancy.
Identify the product and charge
Record the marketplace, ASIN, SKU, included quantity, dimensions, packaged weight and fulfillment method. Keep the fee period beside the charge; a current schedule may not explain an earlier transaction.
Amazon’s Revenue Calculator is an estimate based on product inputs. Amazon’s calculator guidance. The FBA Fee Preview report also concerns estimated selling and fulfillment fees. Amazon’s report role definitions.
Compare the inputs before the amounts
Check that the estimate uses the same product, size, weight, category and marketplace as the charge. Retain supporting measurements and the original fee rows. Separate fulfillment fees from storage, referral and other charges instead of comparing a blended total to a single fee.
Prepare a specific question
If a difference remains, write a short case note with the affected transactions, the expected basis, supporting evidence and the question to resolve. Do not label the difference as money owed until the applicable rules and case outcome support it.
Keep the case reference and response. When the matter is closed, record any correction or reimbursement actually shown, separately from the amount originally questioned.