This stuff is hard to explain without looking at the internal politics and changes happening at schools you want to compare. To compare grades, analysis must be fully contextualized. I personally rather just compare the level of course work. When I see mismatches there and the grading patterns don’t match, then I point fingers. Like if Emory biology 141/142 (or most schools’ intro. bio sequence) and Harvard’s life sciences 1a both graded at a B+ mean, then that is unfair for the Harvard students. I rather go department by department and then course by course. Without having some inkling of how courses are pitched per school, I cannot provide real judgements. I used to compare schools by just looking at general grading patterns, but it only leaves more questions than answers.