Hi Gweedo (love the name),
I'm pretty sure that there is no power crossing over from the switches. They are Ross and the center rails between the lines are isolated in such a way that you actually have to add power to them to make a crossing move. I disconnected the power drops between them to make sure there was no power jumping between the lines. This is really frustrating me as I already have a BPC2 and a CSM2 that are bad.