Hi thehealthcareguy,
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), although the CATs from Kaplan,
MGMAT and Veritas are 'close enough' that they'll deliver reasonably accurate results (assuming that you use those CATs correctly). Keep in mind that the accuracy of CAT results depends heavily on how YOU choose to take the CATs. The more realistic and 'test-like' you make those experiences, the more likely the score results are to be accurate. If you deviate from the standard Test Day 'event' (skipping sections, pausing the CAT, taking it at home, taking it at a different time of day from your Official Test time, etc.), then your scores can deviate too.
With that last point in mind, I have a few questions about how you've been taking your CATs:
1) How did you score on each of your CATs (including the Quant and Verbal Scaled Scores fore each)?
2) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
3) Did you take them at home?
4) Did you take them at the same time of day as your Official GMAT?
5) Did you ever do ANYTHING during your CATs that you couldn't do on Test Day (pause the CAT, skip sections, take longer breaks, etc.)?
6) Did you ever take a CAT more than once? Had you seen any of the questions BEFORE?
GMAT assassins aren't born, they're made,
Rich