I should probably mention how it's set up. You will have a spinbox for Slat Height in the Probing section, and a spinbox for Thickness in the Material section of the Parameters tab. If you set BOTH the Slat Height AND the Material Thickness, then the probe start height will change based on the material thickness.
If either Slat Height OR Material Thickness are 0, then it will default to Probe Height. A high level recommendation I have (I have not tested this in practice, yet) would be to set Probe Height to 0. When Probe Height is 0, the probe movement will begin at probe speed from the current Z position. In most, if not all, cases while running a program, this would start a 5mm (0.197") below Z maximum height, as the g-code filter automagically adds these moves by default. That means that if you forgot to set a material thickness, your probe would start from the highest point possible, and it would probably be obvious that you need to fix it, and it would be the "safest" option.