NMEA Out instance changes not being reflected in MFD NMEA output

I am changing the Instance in NMEA Out and the changes are not happening on the NMEA 2000 system on my boat. Trying to change 2 new fuel tank sensors to be Instance 0 and 1 (port and starboard engine codes). They are changing in the Cerbo but when looking at the NMEA devices on my chart plotter, they are the same as they were before - 5 and 6. Tried reboot. Tried deleting devices, but they just come back the same way - as though the Cerbo remembers everything even when they are deleted.