hey, i never got any score above a 20 on any of my practice tests (kaplan and topscore). and some were as low as 12. i ended up with a 21 AA, 20 TS, and 15 PAT. the only part where i was scoring much higher than i actually did on the real thing was the PAT. study that like crazy, otherwise, if ur scoring above 15-16 on the sciences u'll do great on the real thing. good luck
omar