Need to know how to disable servo retract for auto bed level.

Hi,

I want my servo to stay extended when it is probing the 4 points. I feel that I can have a more accurate measurement of the flatness of the plane if I do this. Do you know where I can disable the servo retraction during probing?

Thank you

Forgot to add, the arm doesnt retract between probing each point of the auto level grid. It ONLY retracts once after it finds Z home and then begins the grid routine. This is the most crucial measurement, once Z home is located, I dont want the servo arm to retract (which it does now).

I really would like to learn how to do that.