The whole point of the LSAC gpa is to more or less normalize gpa's across schools and majors and stuff. I don't think it works really well, but its probably usually in the right direction. As far as I'm aware they have never released their methodology. The school will get your LSAC data and your actual transcript, I've no idea which they prefer to look at. My guess is they'd look straight to the real transcript if its a school they know well and the LSAC data if its a rather generic or unheard-of school. Luckily my GPA went up after LSAC worked their voodoo.