It seems that many of the tower rooms are not opened. It took me awhile to snag tower standard and that was only because I added another date. Now that I want to add an additional date, I can’t find the same room. I am hoping that something opens soon before the latest offers disappear.
They may have blocks of rooms reserved for conventions. Sometimes those open up as it gets closer and the convention doesn't need all the allotted rooms.
Remember they built this tower to cater to convention people.