Unfortunately the Phoenix line is 'minimal' DCC. They understand taking a
long or short address and a few adjustments so you can make it match your
throttle speed. So while running it can follow the commands to your motor
control an mirror the sound to match.
But since they don't support the CV7/8 combination, normal JMRI actions
would have no idea what decoder it is when you place it on the programming
track. So programming via the 'single CV programmer' is your basic tool. In
this respect even the MTH decoders support the normal DCC convention better.
For our ride on scales, these are great sound decoders. But for DCC, I
personally keep with motor-sound decoders for simplicity. I've worked with
dual decoder systems and the usual problem is keeping them in sync for some
changes and isolated for making other changes. Most reliable I've found is a
connector I can open for either decoder so I know exactly which is being
programmed at a time.
Ken Cameron