GmatPrep exam pack: what to expect after 710 & 750?

Hi,
this is my first post on Gmat Club even if I have been using this site since last year. Thanks to everyone contributing in this forum, I always found what I was looking for! :D

Anyway, I'm preparing for my second attempt (first one in December, 640) and after taking e-Gmat CR and SC courses, I tried exam 3 and 4 from GMATPrep Exam pack and scored 710 (Q48 V40) last saturday and then 750 (Q49 V42) yesterday (AWA+IR included). Both this results were..let's say "unexpected", since I thought I was more on a 690-700 range. Clearly I improved more than I thought.

My question is, what should I expect from the real exam, which is scheduled for next tuesday? Is GmatPrep (and especially, the Exam Pack) really a good estimator for the real performance at these levels? I know it's of course the best, but only compared to the others available.

On my first attempt, GmatPrep exam 2 "predicted" a 660 and so it was quite accurate. But is GmatPrep accuracy the same for 600 and 700 scores? I would like to hear some of you who have done the real thing after doing the gmatprep exam pack.

Also, can someone give me some advice for these 2-3 days of calm before the storm? :D Edit: nevermind this question, I found a thread by bb for this :D

Thanks a lot! (if there's already a thread with these things, please give me the link! I spent the last hour trying to find out some answer)