I personally don't feel like the KE needed with most mechanicals is needed in this case. The way the blades deploy simply doesn't burn up the KE the way "traditional" mechanicals do. The large cutting diameter MAY be an issue, but I really dont' think so. It's only 2 blades, and only 2" of cutting surface. A 4 blade Muzzy w/ a 1 1/8" cutting diameter has more cutting surface than that. Ya just don't need the KE....They are essentially a cut on contact, fixed blade head when they hit a deer. You just have the advantages of a mechanical while they are in flight.
The armor plate was the problem on the hog, and I am wondering how you know for sure the arrow deflected as you say it did on the buck?? Did you recover the buck? Do you have the shot on video? It's been my experience that we don't hit them exactly where we think we did.