Re: "longevity ... guaranteeing two years of software updates and upgrades"
Actually, your phone is now effectvely at 83%, because you're only charging to 90% of your new capacity.
4000 mAh at 93% after 18 months = 3720 mAh. You charge to 90% of your new "full" = 3348 mAh. 3348/4000 = 83.7%
Why complicate things? Leave your phone plugged in when charging, charge to 100% all the time, and I bet you'd have more than 3348 mAh after 18 months.
Biting the hand that feeds IT
