Long story short, I can't really decipher the battery usage, on a day, on my XS Max. With IOS 11 (until the last update pre-12), It showed the hours in standby and the actual screen on time; now, on IOS 12, on the Max, one day it showed 5h of screen-on and 1.45 h on standby. After about 1 h of non-usage, the standby time remained the same (why??) while the screen on time was reduced considerably (to 3.5 hours)! I don’t understand how to read this results, or if I have to set up something in the battery settings. It’s not about the usage itself because the battery lasts till bed time without problems, and generally I go to sleep with a 30% residual! Here are some screenshots to explain the situation.