That's odd for expandables to shoot badly. Have you spun tested them? I'm wondering if you got a bad pack that has bend ferrules on the broadheads. This could mess things up for you. Having the blades open during flight might do it too, but why are they opening? Tie the blades shut with dental floss to make sure they stay closed and see if it gets any better.
My first guess would be that the heads aren't straight.

peashooter