converge
The algorithm has changed a lot since 2012, but here is something that I would want you to think about.
Why do you take a practice CAT? There could be primarily 2 reasons
1. You are looking to get a realistic estimate score.
2. You are looking to figure out areas that you need to work on and/or working to increase pacing efficiency.
If you are in the first bandwagon, the only CAT that I would suggest that you take is the GMAT Prep CAT. Because no other CAT will give you a reliable indicator of that degree. However if you are on the second group (as you should be while preparing for the test), the score that you ultimately end up getting is quite irrelevant.
If you could answer a lot of 700-level questions (a term which is quite invalid in most cases and used as a generic measure of ascertaining difficulty), may be you have those concepts internalized. You should focus on the questions that you could not answer and review those thoroughly.
Hope this helps.