GMAT Prep vs. Actual score discrepancy

It is possible that the discrepancy could be 110 points. The Standard deviation for the GMATPrep is +-30 points I believe. I have a few questions about your test experience.

1) Did you do both AWA essays with your GMATPreps?
2) How uncomfortable were you when you took the test? Were you anxious?
3) What were your quant scores on the GMATPrep? It seems like you struggled in quant.

Thanks for the insight.

I guess if +-30 is correct, that means that it would be a greater than 3 standard deviation event for me to score a 570, right? Basically, a 2.5ish% chance that I score as low as I did. This is what leads me to believe, or at least hope, something other than my knowledge base could have caused the lower than expected score.

1.) Yes, I did both AWAs on the GMAT Preps. On the actual exam, I got a 6 or 90th percentile score on them. I honestly felt like I did expend a lot of brainpower on these on test day. While I knew I likely did well here, I felt mentally fatigued after this session. In retrospect, this section was probably much easier than I had anticipated (whereas the math was much harder).

2.) Aside from feeling a bit fatigued, I felt good after the AWA, and I believe the math section started fine, as I hit a probability question around #8 or so. However, I made some blind guesses midway through (a no-no, I know) becuase I felt rushed. On practice exams, I rarely did this. Furthermore, there were very few math questions where I was very satisfied with my answer; whereas on the math practice exams, I could at least narrow it down to 2 choices most of the time and could usually tell when I had an answer correct. Toward the end of math, it seemed like I hand't been asked as many geometry, combination, permutation, or probability questions as I was expecting, which phased me. While I didn't acknowledge it fully in the break between math and verbal, I somehow knew not to expect hitting 680. When beginning Verbal, the test seemed like it was taking much longer than a practice session. At that point I was anxious to be done. However, my time management here wasn't the best and I had about 6 minutes for the last 6 questions. I believe RC went poorly (this is my weakest verbal section). However, I believe CR and SC went about as expected.

3.) My math scores (I believe) were 41 and 45 on quant practice tests. So I'm definitely weaker in math, but these scores are still much better than the 35 I mustered on test day.

As a bit more context, I was using the scoring grid from GMAT's 11th edition on my pretests. In verbal I was between 70 and 90 percentiles, and for math 55 - 80. This is partly why I'm so surprised - I didn't even hit the bottom of my personal range in either section.

Sorry if this isn't the most straightforward, but I appreciate any thoughtful insight or recommendations! Thanks again.