Try playing more Rated Rounds and in Tournaments
where you compete against players within your tier. That might put you
over the top.
WGT has never released the criteria for advancing. I think a contributing factor is the kind of completions we enter. It is possible their algorithm may be programed to stifle those competing largely in RG and Country Club tournaments who generally play against players of all levels (All Players) and have limited entry. But who knows for sure.
Joey