What sort of adjustments are you making? Looking at the 2 matrices you posted above am I reading you’re tweaking in the +/-0.02mm range?
If so you’re in small adjustment range, special care must be taken.
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Are you always finishing each measurement in the same direction to compensate for backlash? You could alternatively enable backlash compensation with M425. Factory spec is a backlash of 0.02mm. That would be a command something like
M425 X0.02 Y0.02 Z0.02 F1 S0, and since that won’t save in EEPROM you would have to issue it manually on startup before manual commands, and put it in the header gcode of Cura or your favorite slicer. Luban cannot do custom gcode, so that’s not an option. -
Have you trammed the X axis perfectly? There is a slope across your measurements from left to right that is a tramming issue. As you can lose tram over time, develop a method of reliably tramming using a reference plane so you can return to tram without requiring a re-calibration. More about tramming can be read in other posts with this search: Search results for 'tram' - Snapmaker: where creation happens. How I do it is here, and other people use soda cans or any 2 things that are the same height: Carriage Tolerances - Unusable Over Distance >75mm From Center - #34 by brent113
Typical layer heights are in the .1-.2mm-ish range. You don’t need to tweak far beyond that - if you’re within +/-0.05mm it will likely print fine.