Well, commercial buildings usually have a lot of below grade work.
Basements and sub-basements. Parking structures and services.

House building contractors usually aren't so savvy. They want to know how tall the wall is. "do i get 8' studs or 9'?"

And the height of the house is usually done on the (can't remember word) the front-side-back exterior drawings. Because that information is only useful to the landscape architect and the city council. (which don't care about the internals of the house at all)

(and you really want your three levels of basement to not be on the plans, so that the city doesn't know about them :-p )