Hi gmatpixie,
First off, both of your Scores are strong Scores, so either one might be enough to get you into your first-choice School. As such, a retest might not be necessary. You're ultimately asking Admissions questions though - and you're interested in some highly-competitive Schools, so you would likely find it beneficial to speak with an Admissions Expert about your overall profile. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/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. If you do choose to retest, then we should discuss your prior studies in more detail first.
GMAT assassins aren't born, they're made,
Rich