Is the probing feature only available when using the OpenBuilds Probe? In an older version I was able to input the thickness of my Probe and now there is no option to do so unless I am using the Probe from the store. I had two separate Probes entered into my BlackBox Controller and neither of them are available for use now. One was for Probing the Z- Zero at G38.1 and the other was a Spindle Mounted Probe that I could use to make Point Clouds with with a movable Probe.
Change the probe type to custom probe, then click on the gear icon (next to cancel button after you change probe type). Z offset is your plate thickness.