That's a great guess, and it would make TOTAL SENSE, but it's actually the opposite. Tightening the screw brings the saddle further back, lengthening the string.So my guess is to loosen the screw to make it longer and tighten to make it shorter? I noticed some of my stuff is a little off. I also changed tunings a lot as well. Will have to do each one to see where they all land.
I should also say the adjustments are *usually* going to be fairly small - quarter and half turns - unless it's in bad shape or you've made drastic string or tuning changes.