Floating will happen only under certain conditions, ccoop, and then it doesn't matter.
And no, your statement on "worst two rounds" doesn't stand.
What is my Average Score?
Your Average Score will be based on multiple best scores within ONLY your current Tier [...]
In any tier, the average is calculated from an (increasing) no. of your best ranked rounds in that tier. An increasing average is only possible if a player hasn't played that no. of rounds in that tier. Once a player has reached that number, bad rounds will no longer be considered, and rounds of lower score will push the bad ones out. Only when he tiers up, the counts will go back to zero and the floating will begin anew. Therefore, a floating average indicates that the fixed no. of neccessary rounds has not been achieved.
An example:
A player starts into a new tier with rounds of 80, 100, 87, 113. Let the averaging no. be 10. The averages will be floating between 80, 90, 89 and 95 (less than 10 rounds played).
Imagine he will play only rounds of 70 and 75 (alternating) afterwards: 75, 70, 75, 70, 75, 70. Now he has 10 rounds with an average of 81.5.
WIth the next round, the highest score will drop off, that is the 113. Therefore,even a round of 112 would lower the average, and a mediocre round of 81 would drop it dramatically to 78.3(!) Now, any further round above 100 would not be considered. From now on, the av. can only drop!
Alas, the first round of 80 stands until there are 10 better rounds.
Continuing with 75, 70... this will happen four rounds later, the average becoming 72.5 eventually.
In further rounds of 75, 70... only the 70s will affect the average until it is at 70.
Therefore, the time of floating average is not significant but an intermezzo, even though it may be long for a Legend (400 rounds in their average AFAIK).