I am not sure the difference between charging but there is a setting for AGM batteries too. Charges to 14.5 Volt for regular, 14.8 for AGM.
I am unsure if it will damage a regular battery if it is set on an AGM setting or if it would make any difference.
The NOCO chargers seem to work good in repairing batteries too. I had one that I thought was weak, & hooked up charger, until it showed fully charged. Seemed I was able to get another year out of it in the boat. Wouldn't hold a charge this spring though.
Do not use the AGM mode if your have flooded lead acid battery. AGM batteries charging voltage is slightly higher which I personally would not want across the terminals.
As others have commented, I also think lower current is better; the slower reverse chemical reation produces less heat and gasing but off course takes longer.
I think all smart chargers these days include desulfation program