Has anybody tried it? Did his/her score change after it?
I mean, I REALLY did not expect to have so many mistakes as I did in the end and I am shocked as I usually realize what mistakes I make in the end. Is there any case that the scores are miscalculated? (trying to make excuses for myself here
It's $30 and it takes a while... maybe even until after the admission deadlines. If anything, they probably just have it there to give people a recourse to protest a score. It MAY make a difference if you erased a lot on the answer sheet (because double marked questions are omitted) but even in that situation it might make it worse (omits start counting as wrongs).
I wouldn't bother. If you did much worse than how you were doing on your practice tests, retake it. Otherwise, don't bother and just adjust your choices of schools accordingly.