Yeah, my old phone is years in the past. The numbers just seem to stick in place longer, but that could be a display issue. All I know is that for two-plus days my five-year-old SE is holding on longer than it has been for 4-6 months.
No complaints, of course. Whatever might be going on is resulting in tangible, real-life results (an extra hour or so of evening usage, less dropping/draining throughout a typical day, etc.).