Hi MvArrow,
The accuracy of an individual CAT result 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. The more you deviate from the standard Test Day 'event', the more your scores can deviate too. As such, we have to take a good look at how you took your CATs.
When you took your 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 when you plan to take your Official GMAT?
4) Did you ever do ANYTHING during your CATs that you can'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?
Beyond those questions, I'd also like to know a bit more about your goals:
1) What is your goal score?
2) When are you planning to apply to Business School?
3) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich