How does the choice of grading scale (such as A = 90+, B=80-90, etc.) affect an undergraduate program?
Using the grading cutoffs that students are familiar with leads to fewer complaints by the students, so I'd highly recommend sticking with it.  There's a lot of anxiety around grades, and the clearer the rules are and the less unusual they are the more comfortable the students feel. The grade scale doesn't actually matter, because you just curve up the exams so that the grades you think the work deserves gets adjusted to the fixed scale.  You can still write exams where a 65% is an A, you just apply a curve so that 65 gets entered as a 90.