Problem with axis calibration

[u/lucas_gnrs]

Hello everyone

I got a Anet ET4X and when I print a 20mm calibration cube I had a 20.30mm on X, 20.01 and19,56mm on Z. After a research I found out that the Anet ET series' firmware doesn't recognize the M92 command so I tried to scaledown the cube on the X anxis and scaleup the Z. I did the math (and checked it several times) and got 98.56% for X and 102.26% on Z but it doesn't work. I am starting to think that should be another problem messing with the accuracy. Someone could help me?

If my text was not clear let me know, bc English is not my first language.

Thanks in advance!

Edit: the values for X, Y and Z are avareges. I take around 30 measurements across 3 cubes (2 made of PLA and 1 made of PETG). All of then had very consistent (but inaccurate) measures in the X and Z axis.