The reason that bareshaft tuning is so helpful is because you determine how an arrow flies at your particular setup without correction from feathers. Charts, graphs, and calculators are limited in their usage because everyone's form and release are unique, and as such significantly affect arrow flight. For example, I get excellent arrow flight, but the charts and Stu's calculator give bad advice for me, and when I follow them, I have broadheads corkscrewing, diving, and doing who-knows-what else. It was tedious and time-consuming to learn to bareshaft, and then fine-tune my setups, but now I can shoot broadheads 50 yards or more and watch them fly like darts all the way.
I've only been to a handful of shoots where there were other trad archers shooting (I usually shoot alone in my yard), but consistently seeing other peoples' arrows fishtailing and porpoising, and hearing arrows smack risers, and seeing them stuck in targets at all sorts of weird angles... that impressed upon me that arrow tuning is not just make-believe, and that a lot of people don't have good arrow flight, and that good arrow flight doesn't just "happen".
Since most of don't use sights, a lot of us shoot instinctively, and often at max distances around 20 yards, it is easy to adjust our mental aiming mechanism to accomodate bad arrow flight. If we are consistent in our release, and are shooting field points with feathers, our minds figure out where to point the bow to get those arrows where we want them... no matter that the arrows are not flying true to get there. But throw a broadhead on that arrow, and the wind-planing kicks in... introducing a very inconsistent variable that cannot be accomodated, and that doesn't group with field points. This frustration can be ameliorated by first pinning down which shaft/length/weight combinations are going to work for you and your bow... by bareshafting.
EDIT: Ha! I just read your original post again... maybe you already bareshafting! Whoops...! Untrue glue-on broadheads can be problematic, too. But once you have the tuning and the truing cleaned up, your problems should go away.