Honestly I just think you're finding out how your rifle performs before warming up. I say try it one more time and you have your answer. Maybe one more time with holdover and see if it's dead nuts on. Then you'll know your holdover for cold bore shots and adjust accordingly after it warms up.
I had plans of doing this same thing today until I pulled a TS and left the 308 at the house. I gotta quit hanging out with that guy.![]()