Buy Shipping protects the seller’s performance metrics by suggesting ship methods with a high likelihood of meeting the buyer’s delivery promise. Buy Shipping uses a ship method’s Transit Time (TT), the ship date, and the promised delivery date to determine whether a ship method is likely to be delivered on time.
Transit Time (TT) is the time the carrier has stated it will take them to deliver a package after they pick up from the seller. The TT is based upon a ship lane, which is the "Ship From" and "Ship To" city or postal code pair.
Buy Shipping will use the order’s "Ship From" and "Ship To" addresses to query carriers for their eligible ship methods that will meet the buyer’s "Promised Delivery Date" (PDD). After Buy Shipping receives the carrier’s eligible ship methods, it will use Amazon transportation data to validate that the actual TT on the order’s ship lane is similar to what was provided by the carrier.
Buy Shipping will use the "Ship Date" and TT to determine the "Expected Delivery Date" (EDD) of the order. If the EDD is after the PDD, the ship method will be ineligible to fulfil the order.
Because Amazon uses internal transportation data to identify eligible ship methods, it is possible for a ship method to be available on a carrier’s website and NOT available on Buy Shipping.
Please note that this is expected as our internal transportation data may be different than what is shown on the carrier’s website, and we are only surfacing ship methods that have been shown to meet the delivery promises provided by the buyer.