I think I've overcome a die rolling fluke. This may have something to do with using my dice tray (which is level), instead of my apartment floor (which isn't). The first 3 NPCs I converted to HARP all came out 6 feet tall and weighing 175 pounds, the first of whom has a name, the other two do not.
Two of the next three had references to either being tall or chubby (so I skipped the direction roll of whichever measurement was called out), and this time I got 5'2", 140 pounds for the average all around NPC, 6'1", 230 pounds for the average height chubby NPC, and 6'10" (with a few rerolls when I thought the die wasn't making him taller enough), 210 pounds for the well built, tall guy.
All of these NPCs are human.