RE: Penetration.I know, I know...hunor me
Though I did not do the KE formula for your setup I would have a hard time believing your situation if I was in it. Your arrows are of sufficient weight....your arrow speed is relatively good considering the rest of your setup....and the heads you are using are probably some of the best out there in terms of penetration with any setup.
The only things left are shot placement and bow tune. If, as Arthur mentioned, you are hitting the far shoulder then no amount of KE or momentum is going to get the arrow to pass through. On the other hand, if your arrows are not flying totally "straight and true" then you are probably loosing energy and subsequent penetration there as well.