Hi, I don't have TFP yet, so I'm guessing, and suggesting tricks used in FP...
When you create a new floor-level / location, does TFP ask if you want to 'clone' an existing level, or is default to just start from blank ??
Can you overlay a 'bare' level at same height as room with inch-high, skinny walls for service run, risers made with skinny pillars, junction boxes etc using imported block.3ds ?? With care, you could align these with sinks, oven / hob / range, power-outlets etc...