I do some work for a builder who also sell mod. homes.The factory wires the fixtures 'hot'at top of basement stairs and bottom of attic stairs,with 3-wire to switch,and 3-wire drops for site installed 3-way.I've been changing them to 'hot at switch' but that's a pain,and time eater;I'd love to site code section to builder to feed-back to modular mfr. to end this.What is it ?