It's a moot point altogether really, apart from perhaps a little personal pride, no one really gives two hoots what you average in league. I have seen plenty of people with high league averages, not able to maintain those in legitimate competition and vice versa.
A proper accreditation system is too hard to complete with TBA's limited resources, so in all likelihood we will never get to rating centres on their easiness or toughness, much like golf courses, so averages will always be subjective.