Before the introduction of the Tour Legend tier, Legend averages saturated at 400 ranked rounds - that is, only a player's best 400 rounds counted in his average, and the average could only move down, never up. When TL was added, that number was increased to 500. Any previous scores that were not included in the 400 were disregarded, and the previously saturated players had "floating" averages (which could move up or down) until saturation was reached again at 500 rounds.
It was only upon reaching saturation at 500 rounds that a Legend would be eligible to become a Tour Legend. An average of 60 was also needed.
When the Champion tier was introduced last week, the calculation of the average was again changed - but saturated TLs remained saturated, and some TLs with floating averages have reported that their averages are now only moving down. There is more to the story that I won't repeat here, but the short version is that it appears that only 200 rounds are now being counted. These 200 rounds were the worst 200 of those that were being counted for any given player before the change occurred, and are being replaced by better rounds as they happen.
WGT hasn't disclosed what the new average threshold is to reach Champion, but they did inform the community that previously saturated players will need 200 additional rounds to qualify.
I don't think it's just a coincidence that 200 rounds were to be added to the calculation, and now only 200 rounds are getting counted. It's as though the program was supposed to be written to expand the set to include the next 200 rounds after round #500, but it got inverted to only capture the 200 rounds leading up to #500.
I'm concerned that WGT made a mistake when it changed the average calculation for TLs to a set of 200 rounds, and that this mistake will make it impossible for any player to reach the Champion tier. The program likely stops counting ranked rounds when saturation is reached. Therefore, if the algorithm asks a question like "is RR=700 and AVG <= 58", which is the kind of question that a program likely asks, the answer will always be no. Nobody will ever get promoted.
If the new average is supposed to only consider 200 rounds, then what is stopping the players with low averages from promotion to Champion right now? Surely the threshold is higher than the averages of the best TLs.