Single Extruder Multi-Material (not just color!)  

Single Extruder Multi-Material (not just color!)

I found and studied a few threads on this subject but am still confused.

1. I have a MK4S without MMU (i.e., single extruder).
2. I want to print a model where the first X layers are PETG, and the remaining layers are Ninjaflex. Based on what I have read, adhesion of the Ninjaflex to the PETG is not a problem.
3. I have done color changes before with just an M600, but this is a "filament type" change that needs a different nozzle temperature, different speeds, different retractions, and so forth (i.e., a different filament profile).
4. I created a new Printer profile, adding "MM" to the name, setting "number of extruders" to (2) and "Single Extruder Multi-Material" = True.
5. In the slicer, I selected "PETG" for Extruder-1 and "Ninjaflex" for Extruder-2. (Note: The profile PETG has nozzle temp 250C, while profile for Ninjaflex is 243C).
6. I loaded the model and "painted" it for extruders using "height range". The object looks correct in the extruder, with "extruder 1" color shown up to layer 99, and then "extruder 2" shown for layers 100 and above.
7. Not important here, but I also set the "Bed Temperature by Extruder" to 0, so that the bed would stay at the temperature for the first filament (PETG).

I sliced the model and inspected the GCode.

• I expected the nozzle temp to change from 250C (PETG) to 243C (Ninjaflex) at the extruder change. It does not. The only M104's in the code are the initial "M104 S175" prior to bed probing, the "M104 S250" before the purge and first layer, and the final "M104 S0" to turn off the heater at end of print.
• There is no occurrence of "M104 S243" to set the Ninjaflex temp. The M600 is there to trigger manual filament at the correct layer, but the nozzle is never commanded to 243C and remains at the 250C PETG temperature.
• Given the lack of temperature change, I am concerned (but unable to verify) that things like speed and retraction may also be incorrect for the second filament.

Why isn't the nozzle temperature being changed (in Gcode) to match the filament in the "second extruder" after the M600?  Do I need to add a "custom filament" to the MK4s itself with 243C as the temp, so that temperature gets set during the manual filament change -- rather than expecting the slicer to add the correct temperature?