What is Pressure Advance Factor... why not pressure advance in mm....??

I know exactly what my pressure advance needs to be in mm...
what is the factor value multiplying from?


in my case, I am printing at 80mm/sec, and I know my pressure advance needs to be 0.50 for that speed based on a pressure advance test in orca slicer

Does that mean my pressure advance needs to be a factor of .00625?

