The midi channels in the mixer GUI are ordered in a strange way. I have the impression they are ordered by the time of the first event in each channel. I think it would be better to just order them by interface+channel and omit unused channels. Currently this is definitely not the case.
Try it now. MusE-1 SVN branch. See your previous meter bug report for more.
Tim.
Submitter has reported this as fixed, closing.