Micromanagement in the freakin' flesh.
All batteries have "Specified" amperage charge limits.
Do you observe the "30%" limit with your flooded batteries? They have a manufacturer's irrelevant limit just like AGM batteries. Battery engineers live in a controlled environment that is not part of planet earth.
Cop cars, fire engines, and ambulances regularly deep discharge their AGM batteries and if you want to see RUDE find out the monster alternator potentials of these vehicles. Government agencies specify AGM because this construction tolerates fast recharging better than flooded batteries.
If these gyro gearloose pocket-protector wielding sycophants could get away with it, they would insist you dress in a green shirt with khaki pants and face Eastward when testing a battery. Did my rant about how they must impress management or face a pink slip, serve to impress? "Gee boss, if we insist customers do this or that we will have fewer warranties" carries a lot of weight. Lifeline insisted my unit be maintained 13.2 - 13.3 volts float at 20c. it was maintained at 13.7 for over a year at +30c and did not lose one GRAM of weight (hydrogen and oxygen).
If you are curious with a depleted AGM impress instant Vmax across it's terminals then monitor battery post (and case if you wish) cell temperature. Battery engineers have to keep busy. When they are not stamping out small fires on the assembly line, they have to make themselves look good to management. Much of what is done is indeed important. Theoretical superlatives is not one of them. Management is not stupid. When they suspected they were not getting a well-rounded report, my phone rang. I was never invited for coffee in the break room.