If your arrow flight is not optimal, you can find a "best" angle for the broadheads. I know this is true because it is what I used to do before I understood arrow tuning. I used to shoot a broadhead and then rotate it about 30 degrees and then shoot it again... until it flew straight. My theory is that I would eventually determine when the blades of my broadhead were most parallel with the initial whip of the arrow, due to poor flight out of the bow. Once I had found an angle that worked, I rotated all the broadheads in my quiver to the same angle, and they flew straight.
Now that my arrows are properly tuned, and I'm shooting off a rest, I feel like I could shoot a spoon for a broadhead and it would fly straight.
Everything else does!