Hi camthewizard,
GMAC has publicly stated that the Official Score that you earn on Test Day is within +/- 30 points of actual ability. Your 3 Official Scores show that you essentially performed the same each time (about 610 +/- a few points). You handle certain aspects of the GMAT consistently well, but you also make certain consistent mistakes. While a 640 - along with a strong OVERALL profile - might be enough to get you into your first-choice Business School, there might be an issue with your Quant Scaled Score.
Many Business Schools view an Applicant's Quant Scaled Score as an indicator of how that Applicant might handle the 'academic side' of the Program - and a Q29 won't impress anyone (and it might also be seen as a 'red flag' at certain Programs). That score implies that you did okay on many of the "math" questions that you saw on Test Day, but you made a lot of little mistakes throug that section and you missed out on LOTS of 'strategy-based' points. Thus, beyond working on your general 'math skills' and note-taking, by focusing on Quant Tactics, you'll be better able to increase your GMAT Score AND better impress how Business School Admissions Officers will view your potential to handle their respective Programs.
If your Verbal Scores are consistently this strong, then you could focus on your Quant skills and potentially retest in a month. Before we can discuss how best to approach this next phase of your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long did you study before each of your 3 Official attempts?
2) Have you used any study materials besides the ones you listed?
3) How have you scored on EACH of your CATs/mocks (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) When are you planning to apply to Business School?
5) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich