Amazon usually rejects sourcing‑cost updates when the invoices you upload don’t meet one of their strict criteria: dated within 365 days, issued by a verifiable wholesaler or manufacturer, showing your legal seller name and address, displaying the exact SKU or product description, and matching the reimbursed quantity—so if any detail is omitted, blurred, or mismatched, the system auto‑declines and defaults to Amazon’s own reference cost, leading to only partial reimbursement.
In order to fix this, resubmit a single consolidated PDF per SKU (do not crop or redact prices), add a cover page explaining why the cost differs from Amazon’s estimate, include proof of payment (bank or card statement), and open a case under “FBA Inventory → Reimbursement Appeals,” referencing your submission ID and requesting a manual review by the FBA Reimbursement Team; many sellers get approvals only after a human investigator reviews clear, unaltered documents, so persistence—and perfectly formatted paperwork—is key.