Setting the startpoint of the EZABL 3x3 mesh
The "EZ" company (TH3D) is trying to make flashing firmware easy by making choices in the configuration for people to set based on printer type. While this makes the flashing more accessible to more people, it does not help people to understand what actually happens in the firmware or what is meant by certain settings. See it as an automated process to add automatic bed levelling to a number of printer models.

To change the bed probing area, you need to modify some specific lines that specify the probe area. How you should change this is explained in this answer on question "How to set Z-probe boundary limits in firmware when using automatic bed leveling?". It would be best to set or increase the constant MIN_PROBE_EDGE. This effectively makes the probe area smaller so you will not hit the bed clips.