When you do a compression test, you're measuring Cold Cranking Pressure (AKA Dynamic Compression.) The static compression ratio (in your case, 10:1) is one of the facters in the equation. The three things that seem to make the most differance are static compression, intake valve closing point, and altitude. But it also includes bore, stroke, rod length and boost pressure.
Here you'll find a calculater. It's for Harley engines, but works on any 4 stroke:
http://www.rbracing-rsr.com/comprAdvHD.htm