P1 and P16 are something AHP does all by itself. It's been there since day one. I tried putting an appliance module on P1 and P16 and installed both in AHP as Appliance Modules. Each had a standard night light plugged into it. I sent an on and an off command, verifed the night lights were off, then checked Find Other Computers and both P1 and P16 showed in green. I kept the two modules for a week and checked Find Other Computers, no odd addresses were found. No timers were assigned, so I did not upload to the CM15 or save the file.
The yellow entires seem to pop up every once in a while. I have no neighbors using X10, either.