As far as I know, AdComs do not want you to convert your grade to a 4.0 scale, and your 8.13 should be higher than just a 3.25 in the US. You talked about the length of your work experience (which makes you a young applicant), but not the quality of the job. The AdComs will care about what you have achieved, what you did, what you led, what you performed in your job, what your qualities represent. If you're able to convey much of these in the essays and on your resume, you'll be good. The way I look at 700 is (I have a 700 as well) that it'll put you in a pile where AdComs will definitely look at your profile holistically and entirely (unlike a person who turns in a 350 GMAT to Harvard which will probably get thrown in the trash relatively quick). A 700 will not keep you out, I don't believe. If you get rejected with a 700, I truly believe that 90% of the time it's because of some other aspect of your application that deterred the AdComs away. So should you retake? Well, I think if you can score 740+, you'll have an easier way to get into top b-schools. If not, I don't see a whole lot of difference between a 700 and a 720, and you always risk the chance of having your score drop.
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