Why Amazon's sourcing-cost estimate lowballs your reimbursements (and how to fix it)

Since Mar 10 2025, warehouse losses before a sale are reimbursed at your manufacturing cost, not retail. The part nobody explains: leave that cost blank and Amazon fills it in — not on your side.

How the estimate goes wrong: it doesn't know your supplier (flattens toward the cheapest lookalike); it excludes freight/handling/customs/duties by definition (already below your landed cost); it defaults conservative (sellers report 40-60% drops). Net: a quiet discount on every undocumented warehouse loss.

The fix (~10 min): In Seller Central → Manage Inventory (FBA inventory view) → for each SKU enter your true per-unit cost of goods / manufacturing cost (in the inventory detail or the reimbursement cost settings Amazon rolled out with the policy). Keep it consistent with what you can back up (invoice/PO/cost sheet). Prioritize highest-value + fastest-moving SKUs.

Documentation is the whole game now. Old system rewarded whoever chased hardest; new system rewards whoever documented costs before the loss. A one-time data-entry habit protects every future claim. Costback helps on both halves — flags claim-eligible discrepancies you file yourself + keeps your sourcing cost documented so claims value correctly. Never logs in, no %. → getcostback.com