I don't think there is a such thing as shooting flat. Think about it like this, the instant the arrows leaves the bow it starts dropping. The drop might be small till it gets out there so far then it starts dropping faster as speed drops. Where it gets confusing is the sights are mounted several inches above the arrow. Therefore the arrows is actually pointed up slightly compared to your line of sight. The arrow will cross your line of sight on an upward travel then again on a downward travel. The distance this happens depends on the bow, the shooter and the distance your sights are set above the arrow. If this was not the case the arrow starting out 4 inches below your sight will always be at least 4 inches below where you aim.