Well first, what inverter do you have? Some have more than 1 AGM setting. Some also have a "custom" setting where you can set the exact voltages per your battery manufacturer's information instead of using the generic AGM setting. Some inverters list in the manual the actual voltages associated with the generic AGM and flooded settings.
I would check the Lifeline informaiton for the precise bulk, absorb, and float settings that your batteries need. Then I would find out how to make your inverter/charger follow those settings.