Buddy if you're still getting only 4.3 hours of on screen time you need to return the phone. That's not normal. It's impossible unless you are getting 1-2 bars, with maybe a 3 thrown in here and there, max ALL DAY LONG and have no WiFi running on top of it. With say maybe max brightness all the way up at all times. No auto. And location on.
If this phones battery had 4 hours OST, as in the actual battery life that everyone was getting including myself, I'd return it immediately and get another brand. Samsung would probably be in serious **** too. They'd never release a the s8 or + with that battery life. It would be a disaster. Especially after the note fiasco. They'd say one blows up, and the that doesn't can't hold a charge. Their most powerful phone ever has only 4 hours OST. Can't imagine that. It's crazy and would be the downfall of samsung.