@jnb said in Mistake in IDEX configuration guide for RepRap:
By doing this you change the virtual length of the axis in relation to the actual length, which results in changing the relation between a virtual mm and a real mm (e.g. 1mm in reprap is 1.2mm in reality).
I think you will find that if you experiment that the M92 settings of steps/mm control the scale regardless of the axis min/max settings.