Thanks for taking some of our CATs!
We do try to make our tests as accurate as possible, so I would say that the scores you got with our MGMAT tests are good reflection of your ability level. I would suggest two things:
1. Go over your exams. Look at the questions you are getting wrong and see what type of questions you missed. Make sure to brush up on these types of questions. For example, if you are getting word translation problems wrong a lot, review the strategies for solving them and make sure to practice those types of questions specifically.
2. Take the two free tests you can get at mba.com. These tests are the most accurate, since they are compromised of actual GMAT questions. This will give you a good idea of your ability level.
Also, make sure, when doing the practice tests, to make it as real of an experience as possible. Sit in a quiet room and take the whole test, don't skip any parts, don't pause the test, and only give yourself two 8 minute breaks: one after the AWAs and one after the Quant section. This will be helpful in preparing you for the actual GMAT testing experience.
Additionally, this article is good for giving you more study techniques:
https://www.manhattangmat.com/strategy-s ... t-prep.cfm
Best of luck with your exam!