What is an OWI charge and how does it differ from a PAC charge?

My husband was charged for the first time with OWI (Operating While Intoxicated) offense and went to court. The judge dropped the OWI charge but convicted him of a PAC because his BAC was . 16 that later gets lowered to . 15. He was fined for some instances and was ordered to have an IID (Ignition Interlock Device) attached to his car. Is a PAC charge as severe as an OWI charge in his record and insurance standpoint? In case he is charged again, is it going to be his second OWI or still first?