Buy Shipping protects sellers’ performance metrics by providing 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" zip code pair. For example, if you are shipping from New York City to Los Angeles, CA, the ship lane could be 10001 to 90001.
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 carriers’ 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 fulfill 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, this is expected behavior as our internal transportation data may reflect differences from what is purchased on the carrier’s website. This behavior is expected as we are only surfacing ship methods that have shown to meet the delivery promises provided by the buyer.