Arrow weight might be a possability, but in my eyes a slim one,
I think arrow wieght is often overlooked by many archers, we want fast flat shooting bows that give us a larger cushion when judging distances. But in my opinion, if your wanting a stable, arrow that's going to connect downrange with a more force, and increase your chances of a pass through you need to bump up the weight a little.
Take a bow shooting 270 fps with a 350 grain arrow, your kinetic energy is going to be somewhere in the nieghborhood of 56 ft/lbs, now change the set up a little and add 50 grains to your arrow, it's going to slow it down some, let's say 10 fps. so were at 260 fps with a 400 a grain arrow now our kinetic energy is around 60 ft/lbs. Not only do you have more kinetic energy but it also going to sustain more force upon impact resulting in deeper penetration and subquently more pass throughs.
The little differences in kinetic energy may be a non issue when using a fixed blade broadhead, but I think it's a very important factor when using mechanicals and talking pass throughs.