Hi Gagan,
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. While the most realistic CATs available are the 6 from GMAC, retaking a CAT that you've already taken is NOT a realistic way to assess your skills - since you will likely see some 'repeat' questions that you have already faced. Unfortunately, seeing even a couple of repeats can 'throw off' the Scoring Algorithm and impact your pacing, energy levels, fatigue, etc. (meaning that they would likely all appear to be better than they actually are). 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 correctly take the CAT in a realistic fashion that matches the parameters that you will face when you take the Official GMAT) - so you can use any NEW CATs from any of those sources next. The
MGMAT CATs are generally regarded as being a little tougher than the Official GMAT, but this recent 680 is fairly similar to the Score that you have listed in your profile (a 690).
1) Is that 690 an Official Score? If it is, then when did you take that Official GMAT?
2) Did you taken any of the Official CATs/mocks from
www.mba.com before taking your 1st GMAT? And have you taken any of them more than once?
GMAT assassins aren't born, they're made,
Rich