You often have little choice how items are shipped even by Amazon.
Because Amazon things including "fulfilled by Amazon" come from different Amazon centers and in different states or countries even if 2 or more items are in same order.
Example: You order 3 Amazon things...
1. shipped from CA
2. shipped from Philly PA (or town next to it.)
3. shipped from somewhere else in PA
and all may arrive on same day and hour to three different days.
Where the address can get snail mail, UPS et al, and Amazon Shipping, odd are good all examples will ship thru 3 shipper.
And if you put shipping directions, only Amazon Shipping will follow them. UPS and most others won't bother. Often drivers doesn't even see them because company ignore them.
Even in Canada, 3 things in same order may arrive different times and use 3 shippers from Different Amazon Canada centers.
Maybe only apply to Prime users...
You can try checking a box at checkout to ship packages in one batch on a given day but that often doesn't work.
need to check each item or order for that option as well.
But above will happen to these items too.
items allow "delayed" shipping as "not in a hurry" so Amazon saves money not shipping in 1-2 days...
You get $1-$2 credit to DL a book etc.
But other things you can't get this or shipped whenever including same to 2 days anyway.
So if order shows 3 days at checkout... Don't count on that. Watch actual data a few hours later or more depending on the order.
I order some things that shipped so fast Amazon Site data can't keep up or wrong.
Like some parts arrived 1-2 days but site still say days to a week or more to ship
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave