I have been testing this to death since my crash, I use tools made from Tig rods
tool offsets are negative if the tool is shorter than the main ref device, positive if longer.
I have only tried negative offsets as that is what is needed, its just the math for the Z when running that piece of code gives a negative so the Z tries to plug rather than lift as it should.
It works perfectly if no offset applied.
If i follow the steps carefully, it works perfectly as i would expect it to :-
Find the surface with the surface probe as tool zero, then select a tool, set the tool number and away you go.
Just DON'T do an auto G31 tool probe with an offset applied.
I've blocked it now so i should be safer, but is the logic here correct in my last reply??