PostScript file for cross platform printing?

I had a tough time printing the PCB layout correctly that I designed using EAGLE software. I designed the PCB on my home PC running Ubuntu 10.4 and printed to a PS file. The plan was to print the board to a magazine paper for toner transfer, on my office printer. So I emailed the PS file to my work address and printed from Adobe Acrobat Professional 7.1. Got my first surprise, the print is actually a slightly scaled down replica, may be 90% of the original. I realized this late after going home and verifying with the actual component that I had. But isn't the postscript (or pdf) file supposed to be hardware independent and vendor neutral? That was my assumption.

I tried various experiments - at my home PC, viewed the PS file at 100% scale and it matched the SMD component pads on screen (I placed the SMD IC on the screen to compare). I repeated the same with my office PC and it also matched. So, while printing something is going wrong. Again at office PC, I used PDF Writer software to print to a PDF file and then print to the Xerox printer, but it also was 90% size. Over the weekend I searched some information online and somewhere I read that PDF prints are not reliable across PCs. Suggestion was to install Eagle in Host PC for printing. Not very convincing.
Came to office on Monday and tried to scale up the print to 110% to get a match. To my surprise the image was way too big - may be 125% of the original. Now I am really stumped. Got the feeling that it was the ADOBE that was screwing up. Just to confirm, I sent the ps file directly to the printer job queue, and it came fine - at actual size! So the PS file was fine, so was the printer. But I doubt Adobe being professional cannot commit such error.

More thoughts and I wanted to try out once more. I have a dual monitor setup at office - both screens having different resolutions. I know that many software have difficulty in working with dual mon setup. Maybe Adobe is one. So I disconnected my external monitor and printed from the PC using Adobe. There you go. The print looks fine! So not a good idea to have dual monitor setup while printing from Adobe.
Lastly, it could be the printer driver also. Since the PS file is handled by the printer driver before sending to the printer, may be its trying to fix the resolution.

Now let me get back to etching!

So, back to the point - postscript file is indeed hardware independent and vendor neutral, just that some software in the chain can cause problems.