Hi lfc,
The scoring algorithm on the Official GMAT is far more complicated than most people realize. Since that algorithm is proprietary, no GMAT company has an exact match for it, thus CAT scores can vary a bit based on the 'biases' involved in their respective designs. The most realistic CATs available are the 6 from GMAC (the 2 free CATs, and each of the 2 that come with Exam Pack 1 and Exam Pack 2), but the CATs from Kaplan,
MGMAT and Veritas are all 'close enough' to the real thing that they will provide you with a relatively realistic score assessment (assuming that you use the CAT correctly).
1) How have you scored on EACH of your CATs so far (including the Quant and Verbal Scaled Scores for EACH)?
2) What is your goal score?
3) When are you planning to take the GMAT?
GMAT assassins aren't born, they're made,
Rich