I have been making contact sheets in photoshop for several years, I have since purchased a new monitor, and a new printer. I am telling this because I want to narrow down the problem as much as I can. When I proceed to print with preview, the contact sheet looks exactly like I want it, however it prints about 25 % of what it should, in that all images are gathered into the top left hand corner, or 1/4 of the 8 X 10 sheet of paper.
That sounds like print settings issue. One possible problem is the document size vs. paper size selection. There's usually a fit to page option, which is what I would look for, but it also needs to know what size paper you have in the printer, otherwise it will not scale correctly. The system print settings and Photoshop print settings can also conflict, so you may need to investigate both.