Question

at last time i have

significantly different volume on the main out  with the use of the stereo channels

  and its not some playback or wires problem

simply thats happend on link position on my l/r stereo chenals of 16.02

Answer 1

Unfortunately, your issue is not clear. Please provide more information with regards to your setup, settings and connections. A detailed description of your issue, will give us a better understanding of how to assist you.