I got an Apple Watch around launch date, which did a full charge in ~2.5 hrs or less. I sold that one, and then bought another recently, and the recent one can take well over 4 hours to do a full charge now. It seems like it gets to 90 percent in 2 hours, and then every percentage from 90-100 takes at least an hour. Is this a new feature to slow charge it as it approaches a full charge?