If both players have different weekend days set, does that add 4 days a week to the game time limits?

It seems this is the case, as I have a game with a 21 day limit, that has 33 days left. That would be 3 weeks plus 2 days a week for their weekends, and 2 days a week for my weekends, which is 12 extra days, making 33 days correct.

But if this is the case...Does it make any sense for my opponent to have my weekends added to their time limit? It doesnt seem right to me, does anyone have any idea what I am trying to say? :)