Nonsense, place 2 orders for the exact same item, Prime for one and Free Super Saving for the other. The Prime order will process, package and ship ASAP, while the Free Super Saving will sit there for 3-5 days in processing.
The carrier method and time with the carrier will be EXACTLY the same for *MOST* items (UPS 3-day/Ground, LS, or USPS Priority) from a warehouse that all but guarantees 1-2 business day arrival, with a few exceptions like media that may go through media saver USPS mail.
They are paying exactly the same to the carrier, you are only paying for them to not sit on your order for 3-5 days before shipping it out their door. Even worst, Amazon's logistics have gotten so bad that it is not uncommon to get 3 different shipments for 3 items in the same order. And you wonder why they feel they have to increase their Prime prices!