Im printing to an HP printer and if I print A5 to an 8.5 11 page the image is not centered vertically. Even though I have "auto rotate and center" checkmarked. Also in properties/effects if I scale down the size of the size it prints out in the upper left of page. i contacted HP and they said its Acrobats problem.
Acrobat respects the "printable area" defined by a printer driver for each paper size, so if yours has significantly-different top and bottom borders that will affect the output.