You’re referring to how much you have to lower the nozzle at the final step of caibration, correct?
5mm is a bit much but probably not in broken territory. The proximity sensor is 1mm higher than the nozzle, and it probably adds a hefty margin to that during calibration so as not to crash into the bed. It is possible your proximity sensor is a bit low, and you can adjust that though it is a bit awkward:
Adjusting the proximity sensor
The simple way to check: when your nozzle is calibrated to be at print-height, slide a credit card (or anything else roughly 1mm in height; I often use a 6" engineer’s rule) under the print head. it should touch the side of the nozzle but be under the proximity sensor. If there is a large gap (half a millimeter or more) between the card and the proximity sensor the sensor is too high; if the rule won’t go under the proximity sensor, then the sensor is too low.
I wouldn’t worry too much about this though, sounds like it isn’t causing any problems.