Laser height 1600mW

A question for everyone, especially for people who still use the 1600mW laser:
What is the correct laser height value?
I’m asking because I still use it occasionally, and after installing the Quick Swap Kit and updating the firmware to 1.17.17, the value displayed on the machine panel was 71 mm. I found information on how to correct this “bug” in Troubleshooting_Guide_EN_V2.0. One thing that worried me was when I set the first value - 23mm and performed calibration, the new value changed to 19mm, the jump was 4mm. Seeing the quality of the calibration lines, I performed this procedure several times. Each time I placed it in a new place on the plywood and covered the existing burns. The value changed as follows: 23mm to 19mm; 19mm by 17mm; 17mm by 14.5mm; 14.5mm by 13mm. I didn’t do any more calibration because the laser nozzle was already close to the detail, and the calibration with 17mm and 14.5mm showed signs of a “good” line. I wonder if I performed another calibration, would I get a new laser height value again?

I have 2 of the 1.6W lasers, one has a focal length (tip to material surface distance) of 6mm, the other one is 4.76mm. Apparently there is some difference in manufacturing tolerance.