I very, very, very strongly suspect that Apple products leave the factor with battery health above 100% and that the Settings app “clips” that figure to 100%.
Indeed, anything else would be stupid.
Apple has to deliver at least what they promise — but every single battery used in modern consumer electronics degrades with time, even just sitting in the original unopened box on a shelf. So, rather than earn a lot of justifiable bad press by selling products with less than their advertised capacity, Apple sells products with more than that capacity, but has the product hold the extra capacity in reserve until time does its thing.
I pre-ordered my first-generation Ultra, got it on release day. Its capacity stayed at 100% for a surprisingly long time. Now it’s at 89%, which is reasonably in line with what you’d expect for the age of the device. I still don’t worry about the battery’s charge … just pop it on the charger when I take a shower in the evening, put it back on afterwards if it’s up to at least 80% (which is typically the case by the time I’m ready to put it back on), and otherwise forget about it.
Same story with my first-generation M1 MacBook Air. It’s down to 86%. I’ve never ever had it away from power so long that it had to shut itself down.
If, in another year or three, either battery gets below 80% and I can’t use the device as I want to … well, that’s why I’ve got monthly AppleCare+.
b&