If you are hitting the deer in the middle of the lung area you should have no problem getting a passthrough.You don't have enough energy to blow through bothshoulder blades and have your arrow on the groundwith any weight arrow imo.
What is your broadhead cutting diameter.With your energy level you need to be less than 1 3/16" imo.I am shooting 28 1/2" @ 58 pounds so my energy level is almost identical.I use 3-39 ACC's with 100 grain Rocket Steelheads and I am buring arrows in the ground after a passthrough.My arrowsonly weigh 380 grains.So it can be done with your setup.
Another possibilty is you are getting excited and applying lots of torque causing really bad arrow flight.With the grip on the Mathews this is more possible than you might think.You are doing fine on the paper but may not be doing fine in the field.I may be totally off base here so don't take offense.

But I am leaning toward shot placement and/or broadhead size.Like others have stated,need more info please.[:-]