The problem is it only toggles on/off (to opposite the current state, whatever that is). There's no discrete command for "multichannel on" or "multichannel off" that works independent of the current state.
By contrast for main power, there are discrete on/off commands. E.g., regardless of whether it's currently on or off, you can tell it "power on".
The lack of discrete commands for all functions is a well known problem for virtually all remotely-controlled home electronics. It's slowly changing, but you still often find "toggle only", non-discrete functions.
No amount of programming by any remote can work around it. The only solution is mfgs must implement discrete commands for all functions.
They don't do it because it makes design of the factory remote easier. They want the fewest buttons, and a single toggle button is 1/2 the buttons for discrete on/off. For each toggle-only command they could provide a separate discrete codes. However there's little incentive beyond providing just sufficient commands for the factory remote, which typically is toggle-oriented.
