One year's worth of AP credits affect rushing?

[naraht]

I know that at some schools, that there are different rules for Rush for Freshmen and for Sophmores. (For example, at some schools Freshmen aren't allowed to Rush until January) Is this always based on Time spent on campus (or as a college student for a transfer) or are there situations in terms of Rush where having a year's worth of credits from AP exams makes a difference?