I'm not sure about the accuracy thing either, but I did have to move my 40yd pin because I was shooting high. What the guy at gander told me was that the string can actually come as far forward as the arrow rest mount before it starts to settle. I don't know a whole lot about any of this but if the string comes that far forward, and the arrow is still attached to the string until the string comes back, it might improve speed a little. Maybe just wishful thinking, but I thought it was kinda weird that I was shooting high at 40 yds after putting on the tamer.