Calibration of z units (1 reply)

I defined "Inch_mode_support" in marlin. And used G21 in my code. Then also my Z axis takes values in cm instead of mm. However my X and Y axis takes values in mm only. Refer examples below:

Eg.1
G21;
G1 x100 y100 z0.2;

When I run this, my X and y axis moves by 100mm each and my z axis moves by 0.2cm i.e 2mm.

Eg.2
G21;
G1 x100 y100 z0.02;

Now my z axis moves by 0.2mm

I don't know why this is happening. How to resolve this problem.