As far as obtaining interpretations of the 48 exemption in regard to max duties and extension, the explanation was obtained so that pilots would stop “misinterpreting” that clause. It was used in such a way as to put the subject to bed. To my knowledge it hasn’t been sighted or officially questioned by the pilot group.
The general feeling is this: at sign on, we have you for the max duty allowed plus two hours if we need you. Then some disclaimer about being physically and mentally fit.