720 shooting for 760+

Add me to the list of 700+ GMATs who are retaking the test. I took the GMAT in 2006 and got a 720. I felt a little disappointed with my score (especially verbal). I started studying hardcore in October and here are my practice scores since then:

PR CAT - 690, 690 (October)
GMAT Prep - 760 (December)
Paper GMAT- 740, 750, 760, 770, 770, 780, 790 (January/Feb)

I've changed my study plan since last time and am concentrating on paper GMATs (mostly for verbal) and challenges. During the last 10 days of studying, I plan to do 5 Manhattan GMAT CATs and 4 GMAT Preps (with reloads). Until then, I'm going to do the remaining challenges (verbal and quant) and 2 paper tests. Also, here are my results from the challenges (kept to time limits on all of them).

Test Correct Total % Correct Mean time msec Percentile
m01 30 36 83.3% 1m 55s 11529 95.4%
m02 33 36 91.7% 1m 36s 9666 97.8%
m03 32 37 86.5% 1m 48s 10836 92.5%
m04 25 37 67.6% 1m 38s 9825 55.3%
m05 31 37 83.8% 1m 54s 11472 94.7%
m06 23 34 67.7% 2m 04s 12484 75.9%
m07 30 36 83.3% 1m 57s 11754 90.5%
m08 23 35 65.7% 1m 58s 11834 81.8%
m09 27 35 77.1% 1m 07s 6781 92.6%
m10 26 37 70.3% 1m 25s 8526 75.7%
m11 28 37 75.7% 1m 55s 11529 76.7%
m12 25 36 69.4% 1m 53s 11336 73.3%
m13 29 37 78.4% 1m 17s 7786 88.0%
m14 28 37 75.7% 1m 33s 9395 81.8%
m15 26 37 70.3% 2m 01s 12151 66.7%
m16 26 37 70.3% 1m 45s 10600 46.2%
m17 28 37 75.7% 1m 39s 9999 50.0%
m18 27 37 73.0% 1m 40s 10053 60.0%
m19 30 37 81.1% 1m 27s 8783 70.6% <---- can anyone explain this?
m20 31 37 83.8% 1m 48s 10847 47.1% <---- can anyone explain this?

I'd appreciate any comments or tips.