Hi AdityaHongunti,
As a general rule, Business Schools will NOT 'piece together' a best result based on the all of the individual GMAT Scores that you submit. While this 640 is a solid Score (and a nice improvement over your prior 600), the drop in Quant Scaled Score could problematic. The Q42 might be seen as a 'red flag' at certain Programs, although if your Overall profile is strong, that Quant Scaled Score might not impact your applications too much.
You're ultimately asking Admissions questions though, so you would likely find it beneficial to speak with an Admissions Expert about your overall profile and plans. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/1) What application deadlines are you currently facing?
You might also choose to purchase the Enhanced Score Report. 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