Hi AbbasAli12,
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 - 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). The idea that scoring 620 on a Veritas CAT somehow "translates" to a 670 on the Official GMAT is silly though - and not correct.
Assuming that you took this CAT in a realistic fashion that matches-up with how you will take the Official GMAT, then a 620 is a solid overall Score though. That having been said, raising a 620 to the point that you can consistently score 700+ will likely require that you commit to at least another 2 months of consistent, guided study - and you'll have to make significant improvements to how you handle BOTH the Quant and Verbal sections. Thankfully, the GMAT is a consistent, predictable Exam so you CAN train to score at a higher level. This is meant to say that your Score Goal is achievable in the timeframe that you've mentioned, but you'll have to be efficient with your studies going forward to achieve that Goal.
1) Are you planning to take the At-home GMAT or are you planning to take your GMAT at a Test Facility?
2) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich
760+: What GMAT Assassins Do to Score at the Highest Levels