Calibrating lens to camera .. have you done it and does it really work ?

I said

"Yes very true as Contrast focusing is at the sensor so there is no shift and that's what a Canon learning article suggest .. AF using contrast in LiveView then repeat using phase detection and that would give you an idea which direction is your lens focusing front/back or exact if no movement .. and as you say many people out there want Canon and Nikon to include that in their next cameras"

Actually that was not in a Canon learning article but I cannot find the actual article link and cannot edit my post for some reason to correct it