As you probably know, the USPS raised its rates this month, and the new Media Mail rates will take effect on Sunday, July 14. I fulfilled an order today (Saturday, July 13) and discovered - to my pleasant surprise - that I was able to use Amazon Buy Shipping and pay the old rate, in this case $ 4.13 for a 1 pound package, rather than the coming new rate of $ 4.63 for a 1 pound package. During previous USPS price hikes, Amazon Buy Shipping always implemented the new (higher) USPS rate on the Saturday prior to the Sunday of the actual price hike. This unfair practice was the subject of previous discussions in this Forum. It would appear that Amazon took the previous comments to heart and changed the implementation of the rate hike programming to the benefit of its sellers. So, thank you, Amazon.
PS: Could you now please turn your attention to the default shipping charged to buyers on books sold by individual plan sellers? It has been $ 3.99 per order for many, many years, during which the cost of USPS Media Mail (and all other USPS services) has roughly doubled. Perhaps an adjustment to $ 4.99 per order, or higher, would now be appropriate.