alosso: Please think of full scores when it comes to the average!
Please think of this in 3 separate compartments.
The WGT average is based on ranked round in one's current tier.
(Saturation comment is correct. Average can bounce around all over before saturation.)
Club handicaps are different. Every club does those on our on own; in BD's case, all rounds over last 30 are wiped out. But we too enter all single play club tournament rounds into our data base.
Finally, a lot of scores don't count. Practice rounds, BOP5, any par 3 course … etc.