Lee is correct, everything but tiers for the reasons he gave. They would quickly shake out the way they are anyway.
As far as averages, I believe there are two games within this site. Shoot against the course for the best you can do, and play against others in multi-player games and tournaments.
I also believe there is nothing wrong with restarting, I think it is safe to say every top amateur (and probably most) restarts very often, everyone has that option to try and get the single best round in for that day. Shooting for average is only one part of this mutifaceted game.
Now for those that worry about a top ten standing I would think it would bother you more that some listed haven't shot a ranked round in weeks and even months in some cases.
In any case, WGT is doing an excellent job in giving us all the opportunity to play as we wish with a quality experience.