I agree with you in the OP. But the scenario above I think is truly impossible...
Really? I admit, I am not too well versed in the whole ranking system, but surely someone can fall out of the #1 spot on the last week of the season, right? Say if ... the #2 player (Player B) won the USO in September and the WTF in December while Player A played poorly/was injured.
I may be wrong though, but I'd appreciate an explanation as to why my scenario is impossible.