I would not assume that ap credits would reduce costs at Haverford. I believe they would only bump a student up into a higher level course.
I wouldn’t even assume a cost savings at a public university either as some have a standard tuition rate for full time students and course requirements may necessitate a full four years of study. Probably depends on the major though.
At my daughter’s public university ap credits usually just serve to reduce the course loads during a semester for her. But she is in engineering with a heavy course schedule and a fairly rigid course sequence.