ALL Legends have to play the hundred round below 60 or not. New Legend will have to play the one hundred in addition to the 400. That is the understanding I have directly from WGT. They would not elaborate on the algorithms but they did tell me this in email with them yesterday:
Phiber,
1. During a recent chat with the community, it was revealed that
players will have to participate in the extra rounds, as well as the rounds that
the community has estimated for Legends to play.
2. As with all ranked
rounds, your best of scores are taken and scores will affect your
average.
3. To make this fair for all Legend players, this extra set of
games was put on all the players.
I hope you understand that we can't
make public with exact details but offer a good guidance into what may be
required.
From,
WGT Member Services