I do think the average/ median test scores *should* back-up the grades. That they don't do so for *one* student or certain students does not mean that they shouldn't for the school in general.

Some students test well and others test poorly. Some do better on the ACT than SAT. But when grades as a whole are not supported by standardized tests, the school system is weak. It just is. That's the way colleges see it too and it is definitely taken into account in admissions decisions at the top private colleges.