Geez, Race has got me again…I need to read the posts more carefully…I thought you were talking about distance from the WALL, not the FLOOR. My comments about the rough-in to the wall are correct. As regards the floor, the bottom of the flange must sit upon the floor and its top, therefore, will project above the floor by the thickness of the flange ring. The top of the flange must not be flush with the floor, nor recessed into it.
NtP