Document is Printing too Small

Ok, I work at Alphagraphics. i have access to many computers and printers. i have used may of these to try troubleshooting this proplem but still need help. I am on an IMac 3.06 GHz intel core 2 duo, OS 10.5.8. I have created a document in InDesign and it prints 1/16" shorter than what is specified in the document set-up (16"x10.5"). I have serched in the print dialog box and its features, and the file is NOT scaled to fit or scaled in any way. I have tried 2 different Macs and 1 IBM with the same results. I recreated the document in Illustrator with the same results. I have printed to 4 different printers with both illustrator, InDesign, and PDF of these files from 4 differnet computers with the same results. I saved the file both with "Print/Save as" and "Save/Save As" a PDF from a PC & Mac. As I create the PDF the size of the document is "16 x 10.5", but as I print from any computer it comes out 1/16" short. What is wrong. am i just missing somthing here. I have serched forums and internet to see similar problems but no fixes. help!