First observation I know is correct,
Coreg and Carvedilol are the exact same drug, except Carvedilol is the generic form of
Coreg. Increasing the combination would mean over 120mg, an unheard of dosage. You are already taking a gorilla dose and that can cause a drop of EF in my opinion. EF ratings fluctuate. I'd ask for a BNP test that is used to determine the level of CHF one has. Usually less than 100 indicates no CHF.