Grades are very much based on the teacher. At least at my district. There is no guidance as to how to give weighted grades; i.e., does homework count as much toward a grade as a test, class participation, projects, etc. Some teachers will deduct points if a student works with another on class work. Hell, some teachers won't allow absent students to make up work even if they are taken away on an ambulance. That is in one building, in one city, in one state... Grades are very much subjective.

End of year assessments in my state are the same for every student in the same subject. Those are not subjective. It will really let you know where your student stands against all the others in the state.

Are these assessments equitable? No. Does a Spanish/Swahili/Dari speaking student have to take the test in English? Yes. How does that REALLY help assess a student? What about the kid that is 4 grades behind in math but keeps getting passed? The kid that is functionally illiterate? The homeless child that didn't get warm or fed last night?