DesignerMAC

I am having trouble with Home Designer Suite. 1) I am trying to set the depth between ceiling below and the next floor at 2 ft but it seems fixed at 12-5/8". 2) I am trying to create either a habitable attic or a 3rd floor and no attic. But an attic doesn't let me create rooms, etc and when using a 3rd floor instead it keeps forcing the creation of an attic, and elements that are related that are problematic. I have been unable to sort it out by reading the help.