Manual confusion  

Manual confusion

"prusa3d_manual_mk3_en_3_04.pdf"

6.3.9.1 Bed level correction (kit only) 
Bed level correction is an advanced feature that is designed to allow advanced users to correct for the slightest imperfections in the first layer. This feature can be found in LCD Menu - Calibration ​ - ​Bed level correction.​ For example, if the first layer seems to be ever so slightly more squished on the right side, you can virtually raise the nozzle by ​+20 microns on the right side. Settings are available for Left, Right, Front and Back. The limit is +-50 microns and even +-20 microns can make a huge difference. When you are using this function, do small incremental changes. A negative value will act as lowering the bed in the selected direction.

This paragraph contradicts itself. One on hand it says 'raise the nozzle by +20', but later it says 'negative value will act to lower the bed'. That doesn't make sense. The bed doesn't lower, but if it did, the gap would increase between the bed and the nozzle, therefore the correct way to word it would be "A negative value will act to raise the nozzle in the selected direction". Super, except now that contradicts the statement that indicates a nozzle raise is a positive entry into the bed correction setting.

Do the bed mesh correction values we manually enter INCREASE or DECREASE the space between the NOZZLE and BED. Thanks for reading, and have a wonderful day!

EDIT: another question is, when we edit these values, how does it affect the center of the bed. For example, if someone changes all 4 values to +50, when the center of the bed has already been adjusted using Live-Z, do we need to then drop Live-Z by -50 to compensate for the bed mesh changes?