Print size changes from print settings to printer

When I attempt to print a pdf file from Adobe Acrobat Pro with the paper size set to 11x17 from the printer properties, the printer always seems to receive a 12x18 file as the input. This problem does not occur when I attempt to print at 11x17 from Microsoft Word or other applications. I have tried adjusting from auto tray select to specifying the paper input tray and changing the fitting and scaling options, but have had no luck fixing this issue. Does anyone understand why this is happening and what I can do to fix it?

The printer at my workplace is a Ricoh C4502.