WGTniv: Your average score is a general identifier about which tier you will be
in, but since we use a time-weighted average (most recent scores count
more) to determine the tier it can become slightly skewed if his most
recent scores are higher than his average.
In the case of that player, his most recent scores were higher than his general rolling average was, which means his promotion was slightly delayed. There is something called "Rank Points" that factors into this equation as well that I can't really get into, but suffice it to say, the order in which you shoot your scores will be partially determinant on exactly where your promotion occurs. For some players it can be more towards the lower end of the window and for others it's more towards the higher end, it all depends on the order of scores. It's a fairly complex system to be honest and it needed to be, but scoring average alone is not the only factor involved.