Hi shadowfax1,
Before I can offer the specific suggestions that you're looking for, I'd like to know a bit more about how you took these CATs:
1) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
2) Did you take them at home?
3) Did you take them at the same time of day as your Official GMAT?
4) 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.)?
5) Did you ever take a CAT more than once? Had you seen any of the questions BEFORE you took the CAT?
6) How many questions did you get wrong in each section because of a silly/little mistake?
GMAT assassins aren't born, they're made,
Rich