ORIGINAL: Straightarrow
It is a far greater possibility that the arrows are not tuned than the bow being out of tune, though both are likely. In my opinion, spine is most likely to be incorrect and the reason most have trouble getting similar POI out of their broadheads. Choosing an arrow configuration off a chart seldom results in a perfect match.
I don't believe it,you didn't mention foc
and that could also be a reason for not getting point of impact the same or very close to the same with field points and broadheads.