An alternative description is that condition z is the degradation itself (even if not reflected in battery characteristics evident in normal use) and the volt capping is just how the BMS manages the degraded battery condition -- just as the BMS limits the battery in various ways according battery temperature too hot or too cold or too much flux capacitor resistance. This is just another way the BMS responds to the changing physical state of the battery.
Agreed
Sorry, but this is just nonsense. If the battery is degraded, in that the battery no longer holds the original charge capacity, no BMS action is necessary in response. The battery has already done what degradation requires, lost capacity. Using the BMS to further reduce capacity has nothing to do with degradation, as has been repeatedly stated (and ignored.)
"Hey, your battery lost 5% capacity, so the BMS is going to remove another 15%, because <made up stuff just to be disagreeable>."