Polarscope issues on EQ5 pro mount

[oyabuns]

I own a polarscope from FLO for a couple of months now, however I have never been able to get a correct polar alignment.
When I screw in the polarscope in the mount completely then the 3 angle is at the top (see picture). 
However with this polaris keeps moving out of the circle when I polar align it. (Polar alignment seems not to work)
When I loosen it I can get the reticule to 0, however the polarscope is very loosely in the mount.

How to best get the polarscope correctly into the mount and get an accurate polar alignment.