Hi Vig17,
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 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 Scoring Algorithm and impact your pacing, energy levels, fatigue, etc. (meaning that they would likely all be better than they normally would be). Thankfully, 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 your posts, I understand that your goal is to raise a 660 to a 750+ in just a few weeks. Unfortunately, that type of improvement in such a short period of time is likely too difficult to be considered realistic. While you might be tempted to take lots of practice CATs, that would NOT be a good idea.
A CAT is really a 'measuring device' - when used correctly, it will give you a realistic score and help define your strengths and weaknesses, but it will NOT help you to fix any of those weaknesses. To raise your scores, you have to learn the necessary Tactics and put in the proper practice and repetitions. The CAT will show you whether your studies are helping you to improve or not. Raising a 660 to the point that you could consistently score 750+ will likely require at least another 2 months of consistent, guided study. Thankfully, the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level.
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:
1) How long have you studied?
2) What study materials have you used so far?
3) For the upcoming application deadline you listed, what is the minimum Score that you would apply with?
GMAT assassins aren't born, they're made,
Rich