I think the glasses helped, but what ever. Heres the way its looking TO ME (I'm not saying its right).

1 box in normal position=~1.08 SHU=multiplier is rounded down to one
1 box at the tallest it can get=~1.2 SHU=multiplier is again 1
2 boxes nested=~2.08 SHU=multiplier is 2
2 boxes at the tallest you can make them=~2.4 SHU=multiplier is still two

Basically, (again this is just my opinion) youd have to have some intense stacking skills to have your multiplier not be the number of bins in the stack.

EDIT: Fixed the typo pointed out below.

Your midnight math seems to work. That looks right to me. But you mean to say 2.4 SHU=multiplier is still two right?

Folks,

Check out Dave Lavery's reply in this thread (note that he has two posts in the thread):

Dave Lavery Response

It confirms that one box is one box is one box.

Aidan
:)

P.S. -- If this wasn't the case, y=ax^2 + bx + c wouldn't hold true anymore!