Hi tanv4u,
First off, both a 710 and a 690 are fantastic scores (they're both right around the 90th percentile overall), so you should apply to any Business Schools that interest you. As such, a retest might not be necessary. Depending on the Schools that you plan to apply to, you would likely find it beneficial to speak with an Admissions Expert about your overall profile. There's a Forum full of them here:
https://gmatclub.com/forum/ask-admission ... tants-124/All of that having been said, these two Official Scores are remarkably similar to one another. GMAC has publicly stated that the Official Score that you earn on Test Day is within +/- 30 points of actual ability, so these results imply that you handled your two Official GMATs in the same general ways. You do lots of things consistently well, but you also make certain consistent mistakes. If you do plan to retest (and again - that's probably not necessary), then you really have to 'nit-pick' your work to define WHY you get questions wrong and what aspects of your studies did not properly 'match up' with what you faced on Test Day.
As an example, you mentioned a bunch of CATs that you took in which you scored 730 to 760. When you took your CATs:
1) Did you take the ENTIRE CAT each time (including the Essay and IR sections)?
2) Did you take them at home?
3) Did you take them at the same time of day as when you took your Official GMAT?
4) Did you ever do ANYTHING during your CATs that you couldn't do on Test Day (pause the CAT, skip sections, take longer breaks, etc.)?
5) Did you ever take a CAT more than once? Had you seen any of the questions BEFORE?
GMAT assassins aren't born, they're made,
Rich