Something odd just happened, and I'm wondering if I'm the one who caused it: I set up my grading scheme so that students could do an extra credit assignment worth 100 points at the end of the semester if they wanted/needed to boost their grade. I just received an email from one of my students whose grade was at 89.93% BEFORE he submitted the extra credit assignment...but AFTER I entered his points for that assignment, his total dropped to 89%! (He only earned 75 out of the 100 points possible.) Did I do something wrong in setting up the extra credit points? What would have caused this to happen??