"Think I'll take your suggestion and avoid
the A code for anything other than motion
sensors etc."
I don't even use them for motion sensors.
When I first started using X10 controllers,
I decided not to use "A" in case someone
else was using it. Of course back then (I
won't say when but it was before
internet.), it was even less likely for a
neighborer to have an X10 product. I didn't
want to take any chances, however.