Definitely losing a lot more with 6.1.2. I never really focused that much on my battery before until I saw how quickly it dropped one day with the newest update. It's odd too since I don't use Exchange at all. I just use Mailbox.
hi guys, i had the same issue once updated to 6.1.2... battery drops by 30-40% during night (network and wireless disabled, airplane mode), and usage was around 1.5h!!!
Then I updated all apps available, and disabled the LTE option (General-> cellular-> eneable LTE --> OFF)..
actually I get major improvement... at 20% of battery left:
usage: 3h 47minutes
stby: 1day 9 hours