Coding echo reading for primary physicians.

Junior coder doesn’t code "borderline to mild left atrial enlargement" as cardiomegaly since query with doctor says that it’s not clinically relevant.

Senior coder says that’s wrong and it should be coded.

1. Which one is right?
2. Senior coder says that well, if the report goes back to primary care follow up and primary care office codes the left atrial enlargement as cardiomegaly – upon chart review for HEDIS, Risk Adjustments, etc. we would run risk "undercoding" bec it would look weird to the insurance that the "codes don’t match".
Question: Do insurances match codes and audit you ?
3. Most of the carotids we read are due to carotid occlusive disease , bilateral so we code I65.23 for all of them. Would that get us in "trouble"?

Our coder keeps on saying oh if we don’t do this, if we don’t do that we will get in trouble. We are all just trying to make an honest living of saving lives, helping people. Are the insurances that unreasonable as to try to "get us" with a code that’s missed or an overlooked diagnosis that was coded from HPI and past medical but not in assessment?

Thanks for suggestions and advices.