There seems to be a bug in the OS X 10.5.5 update that make many printers behave oddly. I have found that printing to Adobe PDF Queues, Xerox, and Oki printers exhibit the same problem: the printout can be randomly zoomed, rotated, or offset each time you print!
The fix I have found that works on all 50 of my office's Mac Pros is to replace the pstops file in /usr/libexec/cups/filter directory with the one from a 10.5.4 machine.
Obviously this is an important system file, so make sure you backup first!
[robg adds: I can't confirm either the problem or the fix; the two printers I have here seem to work fine in 10.5.5.]

