3D taster calibration problem

Hello.
I am trying to calibrate my 3d taster from garant. I have put the dial indicator (with disc ) from x direction etc like in manual. When i rotate 180 it pops up 0.04 mm but if i rotate again and again 180 it stays there. I really don;t understand. why it is not moving anymore from this point if keep rotating the 3d taster. ( hope you understand what i mean)

Its not in center. Adjust it half so the .04mm side reads .02m then rotate back to zero and rest the dial indicator.