Alternator help

Whats goin on fellas, truck threw a check engine code this morning about the heater grid system, just replaced both batteries a few days ago. Wemt up to my local shop here and they checked my alternator and it was charging at 16.20v..... Wondering if this needs to be replaced or is it okay? My hunch says it needs to be done since dodge called for alternators to be charging at 15v. I just want to make sure before i spend the $$! Thanks guys!