I've got a CNC running Mach3.

When I home the x and y axis with the units set to MM, the gantry moves to the proximity sensor, then it moves away a small amount, and slowly moves in to around 2 mm away from the sensor.

When I home the x and y axis with the units set to INCH, the gantry moves to the proximity sensor, then it moves away much further, and VERY slowly moves to around 3/4 of an inch or more away from the sensor.

Is this normal?  I would think that regardless of the unit setting, the gantry would home right where the sensor triggers.