Welcome to the forum dorothy31 ...Now go procure a phase coupler and a pack of x10 filters.
I love good stats.. and I hate not being able to get solid numbers on Home Automation. But, with that said..
I would guess the average X10 customer never uses ether a phase coupler or a filter. Of course I base this mostly on the posts I've read here at the forum... and a handful of informative bits from X10.
For most users... X10 is the alarm company... or the people that make those tiny cameras. Or the Home Automaton.. that allows them to turn the downstairs lights off.. using that stick-on switch at the top of the stairs.
Its always nice to see users that jump into Home Automation with both feet... then join the forum to get the information and support needed. But unfortunately most of the forums (nearly 15 thousand) members don't regularly contribute. I think many come to the forum with an idea or project... and stay only long enough to to get what [information] they need. If your HA setup includes lights in a few rooms, a DS7000, and some cameras...
your a true HA user. You also likely needed phase coupling and maybe a filter or so too.
If your setup required you to make modification's to devices to fulfill your needs... AND.. if you see no completion in you HA setup.. your in a even smaller group of HA users.
Your interests have caused you to learn more about X10 than most users ever do. That makes you a pretty helpful guy to have around. But don't let depth of interest by the few really serious users (like yourself) jade you.
My guess is: Most users...
when they learn they have a phase issue.. merely move the TM751 to a different outlet.