GMAT 740 (Q49 V42), IR 5, aiming for H/W/S: should I retake?

I just finished my GMAT exam and got a 740 (49Q, 42V), with IR 5, AWA probably around 4.5-5.

Sure this is not a bad score, specially given that I studied only 3.5 weeks full time for the test. But I consider re-taking it, as:

a) I do not like my IR score and think that I could have done better if I had devoted c. 1 day to IR just to review my wrong answers.

b) I scored 770, 750 and 770 on the 3 GMAC prep exams I did under timed conditions (with the middle one being the 2nd Preptest in a day), I went pretty confident into the exam for a 760+.

c) I felt extremely competent in Quant section. I exhausted pretty much all 700-800 level Quant Questions on ManhattanPrep (Advanced Quant Book + online question + all 6 CATs) and did not feel that I had any knowledge gaps. In the 3 official GMAC prep exams I did under timed conditions, I scored 51,50 and 51 on Quant respectively. Therefore, I feel rather disappointed about my Quant score (especially because I have an engineering background and generally love math and logic games).

d) I feel that I have one specific weak area in the Verbal part, which is Sentence Correction. In all 3 Official GMAC prep exams, I had exactly 6 Verbal questions wrong, 5 of them being SC. I think that if I had more time to dig a bit deeper, I could score higher on the Verbal part (that was also what I felt during the exam, as it took me quite longer than the recommended 80 seconds for most SC questions.

e) I am only going to apply for HBS, Wharton, Stanford Business School, MIT Sloan And Columbia Business School. I know those are 10 points over the median scores of those schools, but I really want to get into at least 1 of them and don‘t want to get rejected because of GMAT.

So, shall I retake?

Retake because you want to & because you are confident that you can score at least 20 points higher.