Well ... so far NO ONE has explained why a "low and slow" charging style used all the way to full charge eventually reduces the design capacity of an AGM deep cycle battery, while a "high at first" followed by low and slow for the remainder of the way to full charge is what's necessary so as to not reduce the design capaicty of an AGM deep cycle battery.
Math equations and chemical formulas should not be necessary. Why does low and slow maintained all the way to full charge each time - eventually ruin an AGM deep cycle battery?
I understand that liquid acid deep cycle batteries are a different animal in that they do benefit from boost voltages to stir things up a bit during each charge to fulness.