I haven 't got a theory. All I want to know is how much my customers would lose in capacity with a charger set to 41V instead of 42V. If it's 3% or less, it's worthwile, if it's 7% or more, I'll pass.
It's around 7 to 8%. It is noticeable, but it's not a serious loss in my case as I wouldn't start off with buying a pack size of less than 15Ah. I doubt it would be an issue for most users unless they have a small pack and need to get every last ounce of range out of it, or they are long distance riders and need 40 miles plus on a charge. It does prolong life, perhaps as much as doubling it.
However, if you go from 400 cycles to 800, will the average user get much benefit out of that? Say the average person recharges 2 times a week, that would be 4 years before reaching 400 cycles and even then, the capacity is still expected to be 70% or so of the original, so probably still giving useful service beyond that. Do you get many people coming back and telling you the life of the pack had not been as long as they were expecting? How long do people tend to keep bikes before replacing them?
For most people, it's probably not worth the bother. But you may have high use customers who will get through 400 cycles in a year and still want good capacity left after that, who would appreciate longer pack life.