Another weird quirk is that sometimes by increasing the powder, you can lower the point of impact. In other words, I have had bullets from 100 grains hit lower at 100 yards than those shot with 90 grains when using the same bullet.

The 100 grain loads should not fall as fast once you change your sights to get them to hit where you want. And, as stated above, at 150 yards you should see more drop off in the 90 grain load.