My old high school now has two policies in place:

1. Honors and AP courses get +7 added to grades. 2. Honors classes are on a 4 point scale, AP classes are on a 5 point scale.

The school still considers 95-100 to be an A and 94-88 to be a B, so it's totally possible for an AP student to get the bare minimum B score and receive an A and a 5 for their GPA average.