To answer your question, if you practice with official GMATPrep practice test questions and then see those same questions on your practice exam, then yes, your score will be inflated.
Additionally, you may want to avoid a study plan that centers on only doing practice questions. While practicing questions is an integral part of GMAT prep, practicing questions, prior to mastering content is a losing proposition. So rather than jumping straight into practice questions, you will need to follow a study plan that consists of linear learning FOLLOWED BY focused practice.
I’m happy to provide some further advice regarding your study plan, but first I’d like to learn more about your GMAT situation. I have some questions:
1) How many practice GMATs have you taken? Please list the dates on which you took any practice GMATs, the total scores, and the quant, verbal, and IR scores, as well as how you were feeling while taking the tests. Also, please tell me where these tests came from (ex: mba.com).
2) To what programs will you be applying? What are the deadlines for these programs?
3) By when would you LIKE to take the GMAT? By when MUST you take the GMAT?
4) For how many hours a day, on average, can you study between now and your next GMAT?
5) What is your desired GMAT score?
You also may find my article about
how to score a 700+ on the GMAT helpful.
Feel free to reach out with further questions.