Indeed, distance does do funny things to a projectile's flight path. Practise, practise andpractise some more.

i am gonna have to get a spotting scope next. i had to ride down to the target on my atv after each shot just to see where i hit 12x isnt quite enough to see 200 yards...

I picked up a Bushnell Sentry, which goes to 36x from a lady who just wanted it gone. It works well for me.

I think the easiest solution is.... Zero your scope for 150 yards. That seems to be the magic number for muzzleloaders with bullet drop compensating type scopes.

My Omega is zero'd for 153 yds which gives me a six inch pipe from muzzle to 200 yds to shoot through. Using the load previously mentioned.

I "0" mine 2.5 inches high at 100yds with that load when I was practiceing befor I found it liked 110 better.
When you do that it puts your desd on or "0" close to 150 and makes long range a whole lot easier to deal with.
Lee