Good total score but low AWA

Hi All,

I took the GMAT a month ago and got 750, but AWA was very low - 4.0 (20th percentile). I'm not a native speaker and I have engineering degree from an Ivy League college (very technical background). My goal is Top 5 US schools (e.g. HBS, Wharton, etc.) or a couple in Europe (i.e. LBS, INSEAD).

Should I retake the test? I'm confident that my AWA will improve and total score will not be too low, but I may not get 750 again

Any opinion / advice will be helpful!