Sounds to me like the slugs are at their highest point at 100. I would expect them to begin dropping past 100, if they aren't already dropping. You could shoot at 75 and 125 if you wanted to confirm the trajectory. Those slugs are going about 2000 fps, so they should shoot flatter thanmany other sabotslugs.

Mine are 2" high at 50 and about dead on at 100.