There are sooo many things that can contribute to poor arrow flight in cases like this and that makes it is almost impossible to fix via long distance...
I would almost be willing to bet that you have more than one problem going on here-- form, release, consistency of arrow spine, consistency of weight, consistency of shaft straightness, nocking point position, etc. etc.
If I were you I would try to find someone close by that can provide some up close and personal help and IF I lived in the U.P. and was shooting a Northern Mist bow then I would do everything in my power to get up with Steve Turay at NM and seek his help and advice. I can assure you there is no one who wants you to enjoy the ABSOLUTE THRILL of beautiful arrow flight more than Steve.
rick