Agreed, the problem is tuning, and it is common.
You just can't predict how the BHs are going to fly without trying them out.

First, make sure that each head spins true on it's arrow, and then don't touch it. Taking it off and then puting it back on can affect things.

Follow the Easton tuning guides BH tuning section, and you'll be just fine.
It usually doesn't take too much playing around to correct it, so make small adjustments each time so that you don't overshoot themagical sweetspot.