Yes, I agree with that. The two iPhones I had before the 12 Pro Max -- 6s Plus and 8 Plus -- seem to have needed a battery replacement at about the 20th month mark because the capacity was at ~85% at that point. And you being to notice. So yes, doing a battery replacement anywhere inbetween the 1.5 and 2.0 years mark for iPhones is quite expected IMO.