Olivia - I think Kathy's drawing explains it very well. Each floor is 7 feet in height and the bathrooms don't offset each other. It's just that the floor of the bathroom is 10 inches higher than the floor of the suite (as others have mentioned, they probably have plumbing/drains running underneath in the 10 inch crawl space). The height of the bathroom, however, is level with the height of the suite and thus the headroom in the bathroom is 6'2" (7' minus 10").
Kathy - your shower sounds awesome!
Masaki
