Many many AGM batteries out there installed in vehicles with stock charging systems.
Those systems may not be ideal for AGM, but they work just fine.
And they work in -25F and +110F.
I have had AGMs in my cars, trucks and motorcycles for over a decade.
They are just better.
As to your original question.......The Napa battery with extra acid above the plates just allows longer times between filling. Save your money and pop the caps every 6 months.