@ucbalumnus, most majors at American unis take only 1/4 to 1/3 of the 4 years of courses. Granted, there are exceptions (like engineering and other specialized curricula), but someone would typically have to either switch majors a lot or accrue multiple majors to bump against that limit even if they came in with a lot of AP credits. I can see the rationale for this limit. In the case of in-state tuition reductions and merit scholarships, a public school is subsidizing the student.