Players come down when they have played enough good rounds - bad rounds do not count in the end, they are kicked out. To abort lesser good rounds will not influence the tempo of the drop - except that u may start a new round sooner.
As a Legend it's not only 400 rounds but 400 fairly good rounds before a player may be content w/ his average. Hard work if u forget the fun or it!
FWIW, I seem to be stuck at 64.8 now - hard for me to play 65 or better.
Edit: save for the nice 31 on STA just after this post :)