Looks like you were right.
After venting some frustrations at the phone clerk, she got on the horn to MY local post office (like I thought that would do any good) and lo and behold got a usps carrier on the phone and arranged to have them deliver my latest, big, heavy package to my house after it had, as usual, gone back to the post office because it wouldn't fit in the package box at my mail stand. I was completely shocked - I had no idea you could do that since there is no household delivery in my area.
Amazon also pointed out that, although I can't specify which carrier, I can add delivery instructions at order time like "leave at my back porch please." I'll try this next time and hope she's right. I don't want to have to make phone calls every time Amazon sticks the post office with a big package.
I was really hoping to get A to stop farming out big stuff to the post office, but, we'll see if this works instead.
Thanks!
EDIT: Nice try amazon, but this is not working.