It's an AGM battery not an AMG guy. But I know what you mean & are trying to say. LOL For years I used the non-AGM / generic battery charging option on my C-Tek. Thinking that was best. But years later I come to find out that the AGM mode actually (keeps the unit cooler & charges the car battery faster). Because most if not all M cars now-a-days have that type of battery. It's there for a specific reason. So use it & don't be afraid to select the AGM button on your charger.