IMO you need to bareshaft that arrow or shoot it through paper and figure out if it's weak or stiff before anything else. I don't care how heavy or light an arrow is, if it isn't tuned well, it's not going to be a good penetrator. Focus on the tuning first and figure out what flies best, then try to optimize from there. You may have to switch shafts to get what you would consider "ideal". There is some good info on paper tuning on Elite Arrows' website in the sponsor list.
You don't need a heavy, high FOC arrow to consistently kill game, especially deer...I find it more important to find the arrow weight that I personally shoot best with, then try to optimize FOC, then leave it there. I hit a doe in the spine last year that completely severed a vertebrae at an angle with a 418 grain arrow...the broadhead was poking against the hide on the opposite side! Chances are you didn't just get lucky, and your arrow weight is fine to go after deer :D
Craig