In hindsight I think a simple #ifdefine in conditions., with a simple switch statement or ifthenelse in extruder  would solve the problem for 90% of the applications the input to PWM_POS[] is either 

In hindsight I think a simple #ifdefine in conditions., with a simple switch statement or ifthenelse in extruder  would solve the problem for 90% of the applications the input to PWM_POS[] is either