When you load a round with a specific powder load and projectile, and fire it, that bullet will follow an elliptical parabola that is unique to that combination. Adding powder to that charge might very well be doing two things: Flattening out that parabola because of the extra energy, and shifting it downrange a certain distance from your firing point. If you are sighting in at a distance where the projectiles are still ascending, which I believe they are at both 100 and 200 yards, this will cause the larger charge projectile to impact lower. Once they reach the maximum height, or apogee of the parabola, the larger charge should be furthur downrange. As they start to drop, eventually they will cross paths