"Layover" is a term with which I am unfamiliar as it relates to airline rules. There are stopovers and there are connections, but I am personally unfamiliar with the term "layover" -- yet that seems to be a big deal with the OP.

A "layover" is a term you will hear from novices when they describe a connection (e.g., "I had a three hour layover in Atlanta on my way to San Francisco"). I don't think it is anything more than a connection as it relates to airline rules.