Hi dcl5110,
To start, a 640 is a solid Score. Considering the Schools that you mentioned in an earlier post, it's understandable that you would want to retest. 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 Scores in the Q42-Q44 range won't impress anyone.
Before we can determiner how best to proceed with 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) What study materials have you used in 2019?
2) How have you scored on EACH of your CATs/mocks (including the Quant and Verbal Scaled Scores for EACH)?
3) Are you planning to apply during Round 1 later this year?
You might also choose to purchase the Enhanced Score Report for this recent attempt. While the ESR doesn’t provide a lot of information, there are usually a few data points that we can use to define what went wrong on Test Day (and what you should work on to score higher). If you purchase the ESR, then I'll be happy to analyze it for you.
GMAT assassins aren't born, they're made,
Rich