Well, A 700 would certainly help, especially considering the elite status of your target schools, which will open you up to competition from top applicants from all over the world. I guess the potential problem i am seeing in your profile is a misalignment of your past experience with your future goals. I think it might be hard for an adcom to swallow that you will have a succesful software startup without any experience in the software industry. It seems your background is mostly financial services and sales, so you might consider realigning your vision post-MBA to better leverage what you have already achieved professionally.
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Bryant Michaels
Admissions Consultant