WGT answer to my other question about tier saturation :
Thank you for your message. When we originally introduced the Champion tier we made the number of ranked rounds needed to reach Champion tier very low, even lower than the number needed to achieve Tour Legend.
The reason for this was to help Tour Legends enter the Champion tier faster since they already had hundreds of rounds in the Tour Legend tier. This was always meant to only be a temporary number of rounds to change tier.
We have finally changed it so a player needs more ranked rounds to move from Tour Legend to Champion. With this change made it so the number of rounds needed to meet tier saturation to be much higher than previous. This is why some players have noticed that their average has been fluctuating recently.
Next question is : what is the number of rounds needed to meet tier saturation