“Perhaps more unusually, will the adcom know that the school had one grading policy through his freshman year and another his sophomore and junior years, and a third his senior year, all of which resulted in different grade points for the same percentage score? This is actually my biggest concern – not grade inflation per se, but a weird grading history that needs some explanation when it comes down to a fluctuating GPA that may make a difference in scholarship awards.”
The profile that my kid’s HS sends specifically covered all those points. That HS had a harsher grading scale which they changed mid-stream into an easier/inflated one. The profile and the transcript went into detail about what the change was and when it took effect so the transcripts could be viewed apples-to-apples.
Bottom line, the very selective schools are basically looking for the kids in the top 10% or higher in their class. All the GPA and other info is just a workaround for HSs that don’t rank students.
On your merit aid point. Merit aid awards are significantly driven by the metrics that the colleges report (in their Common Data Sets) and that USNWR and others rank on. That means SAT scores, ACT scores, and the % of kids in the top 10% of their class. So again, GPA is just a proxy for class rank.