Amazon keeps a default handling time for your account and lets you override it per SKU in Seller Central, but it applies the account default to any inventory update that arrives without a lead time. That is why a SKU set to 3 days in Seller Central can drift back to 1 day after the next inventory sync, and orders start showing as late against a ship-by date your warehouse never agreed to.
InfiPlex sends quantity only by default, so the Seller Central default applies to every SKU. For SKUs that need their own number, InfiPlex stores an Amazon Lead Time per SKU and per warehouse and includes it on every inventory update it sends. This guide explains the reset, compares the three fixes (account default, per-SKU lead time in InfiPlex, or letting Seller Central own the SKU), and shows how to set the lead time for one SKU in the OMS, for a whole catalog from a .csv, or through the API and MCP server.
