and they make a lot of different broadheads; some that can be accurate for some; inaccurate for others.
They can sell you a bow; they can't always sell you accuracy.

I've found a few inserts that weren't aligned causing BH flight issues too. I knew some guys in a machine shop that made me a nice "squaring" tool that uses replaceable sanding discs. Every time I make a new set of arrows I use this little gadget just to be sure all is square. As for fletch I've used all kinds too. Feathers, 5" vanes, Balzers and NAP 2"vanes. Now I currently use NAP Quik Spin 4". They cost me a little speed but when I release I have no doubt about arrow flight.