It is annoying that it takes so long. The reason they do it is so they can evaluate “bad” questions. For example, for a particular question, if 45% of people choose answer “A” and 45% choose “D”, the question is generally deemed to be poorly worded and the question is thrown out. They then have to adjust the scores nationally. Also, as Tosh said, I think they are looking at the pass/fail line which is why no one can tell you precisely how many questions you need to get right in order to pass a section.
That being said, I wish they would tell you your preliminary score (pass/fail/or too close to call) immediately upon completing the exam. If you got 95% correct, it can be assumed that regardless of the curve, you have passed regardless of how the pass fail line falls (the opposite can be said if you only get 50%). They could then still do their adjustments and give you an official score later. Just my 2 cents.
