GMAT Strategy

I got a 640 on my Kaplan CAT (Q39 V39) which is a 640... Just for fun I looked around and found a calculator that estimated all of the different company practice tests out there and 640 on Kaplan meant a 720 simulated. Huh? I know the Kaplan test undervalues the score but by that much? I kinda like the kaplan test over the MGMAT tests. I dunno, is there a way i can buy them without buying the book?

Anyways, I think this is pretty good considering the highest I got before was a 580 on MGMAT about 3 or 4 weeks ago. (I took the real thing 2 weeks ago and didnt report my score since i thought i bombed verbal on sept 25 or 24).

Just to note... I did retake this kaplan test (free one) but i took the first one about 7 or 8 weeks ago (and I didn't bother studying my mistakes and i didnt really remember the material) so it is kinda like a new test... I got a 530 on the first kaplan take. I'm a little worried since I am still getting the BTG quant practice questions wrong and I go over the time limit.

I am only aiming for a 640 on the real thing.

Finally.. how is the verbal section for Kaplan compared to the other verbal practice cats? Are they considered easier? They looked similar to what the actual thing looked like (except i didnt see any fill in the blank type Qs).