Yeah when measured I'm a 10.5D. ariats I wear an 11D. I've tried boots between 10 and 11.5. I even will try the same pair in multiple sizes and many just don't fit right. Dan posts seem to run narrow but then their wide soles are to wide.Are you sure you’re buying the right width? Are your two feet the same size? (Often they aren’t)
Go to a running company store and have them scan your feet. You may be surprised.