Ger G'day,
Having watched your instructional video for the xxxx time, without blinking this time LOL.. No breaks, coffee or distractions, the penny finally dropped.
What we were doing wrong was not setting Clearance Plane Z Value correctly.I heard you say in the video if you don't set this value correctly the Z will continue going down. (Penny Dropped).
The other thing we were looking for was to set for One Touch Only. That was again an audio pickup, I could have sneezed and missed it. This one was not intuitive to find "slow feedrate set to 0 = 1 touch only."
Cheers.