What we know about scoring the CPA exam is:
1) Each question is weighed for difficulty. Not all questions are created equal.
2) Your performance on the exam (and on each question) is weighed against how others have done – both within your window and outside of that (hence pretests, which create baseline for difficulty/performance).
In that sense, there really isn't a lot of “luck.” A 68 means that you were in the 68th percentile of the candidates that you were compared to. You didn't just get the bad questions. If a question is legitimately difficult, then it will be weighed as a difficult question and “graded” accordingly. Furthermore, at some point, your score is being compared to other people who got that same question.
In essence, the luck component is already factored into your score, because we know that your performance was compared against others' performance on each question (including “unlucky” ones) and overall in your window.
We aren't allowed to discuss specific questions, so we have no way of knowing how frequently questions are repeated during a window. But we can assume that it's reasonably commonplace, or else there would be no real problem with sharing the content of our individual exams. We can also assume that a fair amount of repetition takes place because there isn't an unlimited number of questions AND because it produces better data by which to score. The fact that you were less prepared than other candidates to answer those questions doesn't make you unlucky… it makes you less prepared.
The only way to get evidence on your theory of luck vs my theory of grading, of course, is for you to just go ahead and keep retaking the exam without investing any more study time. If you are correct, and luck alone can swing you 8-10 points, then you will pass within a couple of attempts.
REG - 94
BEC - 92
FAR - 92
AUD - 99
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