So I have been chatting with WGT Customer Service reps about this very issue.
According to WGT - they do not give out information related to requirements to move up in Tier. They neither post it anywhere in their site, nor do they give it out when inquiring by e-mail.
I have talked to 11 Tour Legends about how long it took them to play their qualifying 500 rounds, and not a single one of them played 500 rounds. Most, in their stats, show less than 500 total ranked rounds for their entire career!
The information WGT did give me was that there are too many variables to be able to give specific information on moving up in Tier. Some move up under different qualifying circumstances than others. Some move quickly, while others take forever.There are np two the same when it comes to qualifying.
All 11 Tour Legends did say their average was BELOW 60 when they made Tour Legend.
When you read the posted info about the different levels and Tiers that WGT does have in print, the information is very old. Most of the info about Tier levels, qualifying rounds info, quitting a game, etc... is very out dated, and needs to be updated.