OP. I just tried a mock booking on the WDW site. The $566 price you quote for a standard view room is probably for the casitas, not the tower. I think it's possible you misread the page you were on.
2 nights at the tower, standard view, is $689. (And, btw, standard view in the tower is available for your dates at the moment.)
Just be careful when you're looking at rooms at CSR. The first room on the list was a tower room (king bed), but the rooms shown underneath that were all casitas, not GDT.