You will NEVER get the SC1200A to work with all Date Code Revision Powerhorns.
As long as it sends the two specific address On; Off commands cycle and not the All Lights On; All Units Off cycle. Like the old console. Different firmware and hardware Powerhorns will react differently, to the two address On, Off cycle.
I doubt X10 will change the SC1200A to send the All Lights On, All Units Off commands.
That console has done that since 2005 when X10 made it OEM for Radio Shack and the complaints all the way back then. Got nothing accomplished.
Best to hope for. Would be a Powerhorn with firmware and hardware that reacts properly to the new command cycle and X10 labeled it "SC1200" Compatible". That could also possibly bust it for the older consoles.