Hi Mck2023,
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 (the 2 free CATs, and each of the 2 that come with Exam Pack 1 and Exam Pack 2) - but for future reference - 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). Thus, while you should certainly use the 2 free CATs from
www.mba.com, you can also use CATs from any of the sources mentioned here during your studies.
One of the keys to making the results as realistic as possible is to take each CAT in a manner that matches what you will face when you take the Official GMAT (take the FULL CAT - with the Essay and IR sections, take it away from your home, at the same time of day as when you'll take the Official GMAT, etc.). Once you have your score, you should report back here and we can discuss the results and how best to proceed.
You ask an interesting question about how to handle a situation in which your electricity is cut. Is that something that happens often to you?
GMAT assassins aren't born, they're made,
Rich