in emc i set the steps per inch rate so when i ask for 0.100 i get 0.100
steppers motor slipping with no feedback, will travel short or
<0.100 when asked for 0.100
a controller with feedback resolver or encoder if encoder says it did not travel 0.100 it will travel extra til it reads it moved 0.100
i had a mill where feedback encoder if stuck the mill would jump far, sometimes inches. basically if encoder is not reading movement it gave it full power til it read movement of required amount.
i had encoder replaced and problem went away. although sometimes though encoder is dirty or has loose screws.