Hi singh8891,
To start, 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, 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).
From what you describe, it sounds as if you took the first free GMAC CAT twice. Even though the 'format' of the Exam may be different, the pool of questions that the Exam draws from is the SAME. Retaking a CAT that you've already taken is NOT a realistic way to assess your skills. Seeing even a few 'repeat' questions can 'throw off' the Score Algorithm and your pacing, energy levels, fatigue, etc. would likely be better than they would be under normal testing conditions. This is meant to say that the 730 is likely not a realistic Score. GMAC has publicly stated that the Official Score that you earn on Test Day is within +/- 30 points of actual ability. Assuming a similar 'swing' in how your CATs function, your other 3 CAT score results show that you essentially performed the same each time (about 640 +/- a few points).
Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) What study materials have you used besides the books that you listed?
2) How have you scored on EACH of your CATs (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
3) What is your goal score?
4) When are you planning to apply to Business School?
5) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich