I'd really like to see the exceptions. I've never come across anything but NEC protocol for any Samsung TV in the past 20 years, going all the way back to their CRTs. Do they subcontract some models to other companies that use their own protocols? I have seen several other protocols in older models (older than 20 years or so).

In any case, do you suspect that the on/off codes for your model are an entirely different protocol? That would be almost unprecedented. It's far more likely that their cheaper models simply don't have discrete on/off.

Also, since you're using RTI, can you not simply use a variable to keep track of the on/off state. In the JP1 world we simply use toadtog bits. Works fine for TOADs. Surely RTI can do something similar.