On my raspberry pi projects, I often include a power supply section on the board, generally isolated connected only by +5V and GND. The power supply section sits on above of the pi's ethernet and USB jacks, so the board needs to be stacked higher than a board that did not include the power supply. If I want to make my board into a power-supply-free variant, I can get the dremel out and cut off the power supply. Recently, I've started adding a line of drill holes to partition the two boards, making it potentially possible to snap rather than to dremel. There's a break in the line of drill holes to let the +5V and GND pass between the boards.
Anyhow, this time my board house reviewed the design wants to assess me a fee for having two designs that are panelized together instead of just one. The fee exceeds the cost of the boards.
My contention is that since my boards are electrically connected, and electrons flow between them, they are not two independent designs, but an integrated whole. I don't really know what the standard is within the industry on this. Am I right, or am I wrong?
Scott