IMHO lot of members overthink the issue.
When smart chargers do exist, trucks have voltage regulators build to "keep the preset voltage as long as you can" all with some tolerances, so you will see small voltage variations .
So the amp are results of draw and cables resistance per my observation.
For years I've been driving Ford trucks and Mercedes sedans.
Mercedes has regulator set to keep 14V and I had 1 battery last 13 years with other owner reporting 17 years on factory battery.
My older Fords were charging at 14.5V and no battery lasted longer than 5 years.
Go figure.
