I don't see issue with your battery usage. The phone after 12 hours, it's how it is and is subjected to what apps you have running in the background and features on like WiFi scanning, Bluetooth and GPS.
You will get high SOT only when you use the phone with the screen on. It does lose charge in idle too. You're still at 70% after 12 hours is pretty neat.
I got 8 hours for the first time when I hammered the device on the weekend. Otherwise I see same or similar numbers as you.
Other things I have set, brightness to manual, Bluetooth off unless I use it, WiFi scanning is off and is set to always off when screen is off, GPS is set to battery saver.
Edit: try turning off the Animations from Developers to really stretch the SOT.
This device has the best battery life of any Blackberry I've ever had -- significantly and finally, except perhaps early versions when I think I could get 24 hours. But then, they couldn't do much besides email, text, and talk.
I use twitter, Facebook, instagram, emails, web browse, every day for work and have never had to charge the phone before bed. It's in the 20%+ after 15+ hours. When hardly using any of the above, I went to bed at 70%. The battery is between great and insanely great.