GMAT is just one part of your applications, and the admissons review your WHOLE PACKAGE. if your GMAT is in the 80% range, i think it's ok. 750 even can't guarantee that you can get the interview, and 680 also even can make u get the offer from M7.
I think the most most important thing is thinking about WHY issues, finding your dazzling points, which are really unique, different with others. and showing all the pionts in ur essays and interviews, then, you will get in.