Basically, the idea is to discourage essentially spamming regrade requests as a zero cost effort on the part of the student that occasionally pays off. That th

Basically, the idea is to discourage essentially spamming regrade requests as a zero cost effort on the part of the student that occasionally pays off. That the teacher has made one mistake implies the teacher may have made more than one mistake, and there's some probability that those errors are in your favor. And if its really correctness you're worried about, rather than just going for a better grade, then you should be okay with a full on review. But you should be confident that there are errors, rather than just winging it for the occasional payoff.