well..... i dunno what to say.
I've installed the UTG today and the Ultimak M8 , both to 2009 vintage bell lifestyles Poly techs...... and they are both level, muzzle to chamber and parrallel to the receiver plane/bore center. I also checked and triple checked to make sure i wasn't missing something. I did have to slightly enlarge the UTG side hole to accomodate the ARMS 18 side screw i replace the UTG screw with in order to get the side to side level on the UTG.
I did not have to use shims at any point on either mount to achieve both level or parrallelism to the action/bore. The utg model has the "UTG" label right side up and was purchased thru an american online outlet as per info from my client who contacted me as soon as he saw this thread panicking about this new issue with railed handguards.
Not trying to take away from the potential value of this video or method, but i have not personally run across it when fitting these mounts to chinese rifles.
However, if your rifle exhibits this issue when installing one of the handguard rail type mounts...... this solution is a good one.