probe lifting after g28

Hi all,
can someone please help, I am building or have built an I3 printer with auto levelling probe and mixer nozzle as a follow on from my standard I3 clone. my problem is that the probe which I have set to use Z min pin, the auto levelling works fine but the G28 homing although going through the routine as I would expect sets the X and Y to 0.00 but after setting the Z the nozzle to 0.00 raises 5mm above the bed before coming to a rest. re sending the G28 command the same thing happens and even when sending the Z axis home command nothing changes the nozzle always ends up 5mm above the bed. I have trawled through the config file but have not spotted the reason. Does anyone else have this problem or has someone else had it and found the solution.

The solution would be to send a G92 Z5.0 ( if this is the real distance ) after G28 in slicer startcode. That way you have perfect control over nozzle height.

thanks o-lampe,
I will try that

In marlin I had to configure my z zero position.

When homing it would always stop a distance away from the bed but when sending G1 Z0 it would not touch the bed until I configured the offset.