So look up the electrochemistry.That's the definitive measure for float voltage. Also I advertised the home system without trying to attach it to a vehicle system.
I take your point of "wear-in" products. But be aware that the vast bulk of wear-in occurs in the first hour or so of engine life. The real issue is the cleanliness of the production line. This determines the chances of manufacturing "debris."
The electrochemistry for a lead acid battery (regardless of construction) will yield a float 100% voltage of 13.2 VDC. Note there is a temperature dependency. Those numbers you cite are system design connected to a charging controller's programming. Go look up the chemistry involved. Charging...
Battery terminal voltage without current in or out tells you state of charge. AGM batteries are susceptible to overcharging more so than flooded cell batteries. Ford has then programmed the charging strategy to take it to 80% ~12.8 ~ 12.9 VDC.
21.7 &22.2 Colorado & Kansas Speed limit 80 & did that, Missouri speed limit 75, did that. Illinois & east speed limit 65 and followed that. Crossing the top of the Appalachains sometimes 40.
This truck is a cruiser! A few years ago I did a speed run, 1,000 miles a day from Denver to Illinois to Myrtle Beach SC for a ships reunion. The truck just kept going and going and going... Mine's an XLT and the seats are good for me.
The issue is it is quite rare to go from high power to engine cycling off immediately. If you're parking or otherwise at low power the turbos are not spinning to any significant amount. when you draw conclusions from low power to off versus high power to off, you are talking apples to oranges...