Well, call me a simpleton, but, assuming your rest is good, you are not resting on the barrel, and that your rifle has no hidden issues, and your scope is 100% -
1) if I understand correctly, you sighted in with one bullet/load, then shot a different bullet/load and they don't hit in the same place... and you thought they would hit at exactly the same point? thats a NO-NO assuming they will hit in the same place, most loads will have a different point of impact - especially at varied distances, unless the load has exactly the same pressure, velocity, and BC - So, sight in for the bullet you are using. I have seen with my own eyes a diff of 8" at 100yds using two factory loads (both 140gr) in 7mmRM, and 6" off in a 325wsm with factory vs. reloads (both 200 gr bullet) - again, sight in using the bullet you plan to hunt/shoot with!!!!!!!!!!!!!!!!!!!
2) physics here - with a normal set-up on a high velocity scoped rifle, to be bang on at 200 you will be around 1.5-2" high (+/- a bit depending on cartridge) at 100, period. One will always see high impacts at 100 to be dead on at 200 - that will not change, never will, nada nada. Its called gravity, it is a constant all over the globe
3) see point #1 again. Read it again.
4) If you believe the theories explained about the possible alien abduction of your bullet and making it backspin in transit, or the altered laser trajectory with a bullet rising as it goes farther out, I suggest you wear your tinfoil hat to the range next time
problem solved!