My exact thought. Wooden floors — not even strong enough to bear the crowd — and the cesspool large enough to fit 60 people? That's not the place for king's accommodation, even in time when everyone was used to the smell of the stables. If anything, the ammonia would corrode the hell out of any metallic objects in the building, like nails.

Without reading German links, I suppose that either some architect had had a bright idea that a giant 640 KP latrine should be enough for every occupation, and thus wouldn't ever need to be scooped, or that people were mostly crushed by rubble, and the adjacent common-sized latrine also broke.

Though in some periods latrines were used to make certain chemicals, and therefore the building could be seen as what we now call a chemical plant.