Hello Digisal
I agree with JimC it is wise to change Housecode/Unitcode to something other than A1 ..
That said my home is full of Socket Rockets including 2 in each PR511 that I have(hacked PR511 if anyone is wondering).
Use them in electrical,heater,utility and work areas and some lamps.Also some outdoor for mood lighting(low output bulbs).
Use AHP for timer and dusk-dawn operation and of all my X-10 the SR are the most reliable.
Change your HC-UC to lets say B1 and update your hardware configuration to your area plus check transceived codes you use including B.
It should work no problem if you say that manually turning it on works all the time.(No noise issue apparently).
So change to HC-UC your choice,check hardware config to your area and check HC-UC used by you.Create timer and/or macro's and voila!
Hope this helps .... You can get X-10 to be reasonably reliable (close to 100%) but it takes a bit of work.
cheers
teez67f