Why is the torikumi this way

[AsaMoe]

Noone asked so far, but i am interested:

Why does Tochiazuma fight against Kotoosho on day 11. Wasnt there a perfect chance for a 4 day-tournament of all Yokuzuna, Ozekis and sekiwakes/leaders ?

[Chiyozakura]

I can only guess but I assume that they wanted to keep the possibility to have Kotooshu face Kisenosato in case Kise stays in the yusho race. I think it is a good decision. I remember Kotomitsuki's first Makuuchi basho when he was runner-up with one win behind Akebono without a direct matchup.