Ok, I believe I'm on the same page as you.
I believe I mentioned this before that I could literally put a stop watch to charging when using my inverter/ charger and set it 100a charging with balance of power going to my loads. 1% SoC = 5ah (500ah bank), I just did this a month or so ago when the sun was down and no help from solar. The bank was down to 60% SoC which meant that 40% or 200ah was needed if my batteries are still near the rated capacity. 2 hours later almost like clock work the SoC was back at 100% switch over to float accepting .05-1a current fluxing within that range.
If this was not the case of full or near full capacity of the rated batteries would the charger not keep going or shutdown earlier?
If claimed Cycle Life : >2000 (80% DOD); >3000 (70% DOD) for my batteries. With fractional C use I daily cycle 35-40% DoD (175-200ah) and I figure that there is over 500+ full cycle combing years of use now, how much capacity is gone?
You can read all the internet forum post you want and think it's all exaggerated (which some of it is), until you live off of them everyday with set parameters and safe guards in place. You'll never go back to dead lead.