Help me figure out my zero problems

[reapur]

Hello,
I have an AR15 with a red dot, both a holosun 503c and eotech xps3.

I've been consulting ballistics calculators from Federal, Hornady and Sterlok pro on my phone.
I'm pretty sure I have a the ballistics for the M855 figured out since it's available all over the internet and strelok pro has it in its database.



So According to these calculators for a 200 yard zero, it should look like the above picture.
The way I see it, I can zero at 25 yards if I when I aim at the bullseye, I let it shoot 1" high, right?
Then at 50 POI should be almost right at POA, just .3 off.

Well I went out today and got the zero at 25 yards, where the POI is 1" high.
Then I went to the 50 yard range, and POI was 6+" high!
I went back to the 25 and it was right on at 1" high, I go back to the 50 and POI is still high.

How is this supposed to work?

Thanks