Unstable calibration of CH throttle

I recently bought a CH throttle quadrant, but I'm having some trouble with calibrating the right throttle lever. I've got the latest CH drivers installed and I calibrate it in FSUIPC 4.931 by moving the levers up, set the top value, then moving the levers down and setting the idle value.

The values from both throttle levers differ, but I guess that should be solved by the calibration, but when moving the right throttle lever to idle, the value is very 'jumpy', I don't get one steady value, it keeps jumping up and down. I tried to set a value for it, but in the virtual cockpit the right throttle lever is also jumpy, it keeps moving in idle position and when I move both throttle levers up, the right one is lagging behind on the left one, even though the position of the levers is the same.

How can I calibrate the lever that it stops jumping in the idle position and will move along with the other one?