Charging 12V step change - 14.0 to 13.5 volts.

Know what.......designers can not design to the whims of every potential owner.

And you think that your situation qualifies as a scientific study.......or even a statistical one ??
Hint: It is neither and is just another anecdote.

And I know that this will be wasted effort but just incase you might actually benefit from some facts:
One of the reasons that the change was made is:
There is an inexpensive and readily available remedy for batteries that don't get charged enough in "normal" use: A battery tender.
OTOH, there is NO remedy for a battery that experiences a very slow loss of capacity because of OVER charging.

You can stop your incessant and pointless whining whenever you want.
It is doing absolutely no good.