All aspects of your profile are impressive: 3.8 gpa from the University of Michigan, 4 year's Work Experience, Extra curricular . You seem to have a clear plan for your future, and you are expecting great recos, too. You have touched 700 GMAT score which is good.
However, the only thing that is bothering you is your 78th percentile for quant because you were a a math major in college.Due to demands of your current job you don't want to spend anymore time on the GMAT . That's fine. You are thinking in the right direction. You should be spending this time in building memorable essays and applications because essay writing takes mush longer than most applicants think.
There is no need to feel embarrassed about your quant score. If you still are, you may explain it in your optional essays.
I hope it makes you feel a little bit better.
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