Should I take the GMAT a 4th time?

Hi,

I am looking to get some advice on wether to take the GMAT again for a 4th time. I just finished my 3rd test and I think it went surprisingly badly. 640 V40 Q37.

Last year I took the test twice:
1st time - 600 (cant remember exact breakdown, but favored verbal)
2nd time - 680 V41 Q41
Graduated in 2005 from a top 25 undergrad school, majored in film production with a 3.55 GPA and have been working at an internet company for the last few years in a product and business development role.

I applied to 6 schools last year including HSB, Stanford, Columbia, Haas, UCLA and USC (round 3). Unfortunately I wasn't accepted to any of these schools and I was also later told by an admissions officer that one of the reasons was that I didn't have stellar quant scores.

I plan or reapplying to UCLA and USC in round 1 this year and I took a management mathematics UCLA extension course this summer to prop up my math scores. I got an A in the class which was good. I also wanted to improve the quant score on my GMAT and have been killing myself for the last 6 weeks studying every day after work and all weekend. I have also been working with a private tutor to address my specific areas of weakness. I was getting in the 700 range on my last couple of practice tests.

I was really surprised to get a 640 today. I wanted to write about the GMAT on my reapplication essays as one of things that I worked on to improve my candidacy, but now I feel like I cant bring it up. I think this was a fluke test, but the real question is wether to take it again for a 4th time or is that beating a dead horse? I think I have it in me to get a higher quant score, but would that be drawing too much attention to this section of my application?

I am really perplexed about how to best proceed and would really appreciate some advice.