Had a little more conversation this morning with the reviewer... We're not in a hurry about it, so it's a slow conversation, via email. He shared these from the commentary for 1010.1.6... And despite the definition of "occupiable," he's adamant that the bathroom will be "occupied" by the dwelling unit residents for reasonable periods of time (unlike a closet or something). He even pointed out that the commentary's specific reference to toilet rooms NOT being occupiable, in older codes, has been removed in more recent codes.