What do you think about GPAs being non-standard? Test scores calibrate between schools - GPAs only kind of do. I remember many classes that were taught by two

What do you think about GPAs being non-standard? Test scores calibrate between schools - GPAs only kind of do. I remember many classes that were taught by two separate teachers: one teacher consistently gave students higher grades. The other teachers students consistently did better on the AP test - much more strict with homework and test scores, but it ended up positively impacting the students.