BB Dual v1.1 Hybrid. Running Alex’s firmware (MBL). Firstly, when correctly set up, how high off the bed should the nozzles be. i.e. when running the auto home from the LCD, where should nozzle 1 (left) be. Display say 30,30,0. I assume pretty close to the build plate? So I level the bed, using a strip of paper, and the 9 points across the bed. Every thing looks good. When selecting the autohome option from the menu, the nozzles are just above the build plate. Prints are satisfactory. All is well for a few days, then.. I turn on the printer tonight. select the auto home and the the nozzles end up a good 2-3mm above the build plate,and nothing prints, obviously requiring re-leveling. why?? (this is with the same room lights on as originally levelling, blinds closed and dark outside. Also tried with the lights off!. Also with white & black tape under the IR sensor. Does the sensor see the glass of the surface of the heated mat) This is really getting quite annoying. Any idea why. I always perform an autohome before every print, but i shouldn’t need to re-level the bed every time. Is there any way to display the MBL values ? An aside, looking through the menu, what does Prepare -> Set Home Offsets, do. Mine simply screams/Beeps at me than displays “Err: Too far!” And during printing, what does Tune -> Bed Z and Tune -> Babystep Z do?