The L322 calibration using the All Comms process is mostly automated....
When the system is placed into calibration mode using diagnostics, you tell it the rim size fitted (lets say 19") and the vehicle will automatically raise to a datum height. This is a certain height reading as provided by the height sensors....Lets call this figure 'X'
You then grab your favourite tap measure and measure from the bottom of the wheel rim to the lower edge at the centre of the wheel arch and put this figure into the Calibration Screen, lets say you measure 767mm....
The EAS ECU then does some funky maths and knows that when at reading 'X' the vehicle is at 767mm.....it knows that when sitting on 19" rims at standard ride height it should be 753mm, so in order to be at standard ride height it needs to move until the height sensors are reading 'Y'....and so it settles down to standard height....and using the power of extrapolation it automatically works out what the height readings should be for Access, Motorway and Extended.....job done.