Actualy front of center is a big deal at close range. For example its a little extreme but if your arrowhas a6% front of center its not recovering near as fast out of the bow as one with say a 15% FOC. Also with that low of a FOC your going to have much more oscilation and a less stabil arrow which can cause penetration problems. Granted FOC isnt the only factor in an arrows stability but it is a pretty big one.