Here is my result.
First time I updated via OTA and the battery was not working well.
Now I flashed the Codes 1219 and 1227 and it's way better.
I'm a heavy user with Wifi enabled 24x7 and I do play some games.
I'm charging my phone during night and using the whole day and it's 30% remaining before I go to sleep.
So it's better, I still expected more, but it's seems good.
Heavy user, Wifi + gaming = 18hours.
Thanks for your feedback!
It confirms that the battery drain again problem gets solved by FLASHING
the 20171227 version.
I'm marking this issue as solved