Range Report .30 180 Accubond bc

[Palmershunter]

I have a 300wsm tikka t3 that shoots a 180 accubond at 2950. Using ballistic g1 calculations on my iPhone I am 3 to 4 moa low out to 1100 based on a 100 yard zero.
Scope tracks fine. Not sure what's up here other calibers data are fine.

Any ideas?