That looks like perfectly normal battery to me. The main thing to achieve the best battery life is to keep the brightness down and heavy cpu usage down. What was your brightness set at? How were you using safari/Facebook app? Scrolling and loading pages at will or mostly idling? All of these different factors/behaviors in which you use apps will dramatically affect how fast or slow it drains the battery. It's not always the iOS version or app you are using that's draining your battery. It's the behavior in which you use your phone. That's why you see so many differences in usage times. Some people listen to audio with the screen off and you see those 8-10 hr batter numbers. If you have the screen on at all times on the 6 at 50% or less brightness good luck getting more than 7 hours usage! Looks like you used the app store to download some apps. That will spike cpu usage and drain the battery faster too. The A8 is very good at idle power consumption but it eats the battery when it's drawing full power!
I keep seeing all of these posts wondering if battery life is better in this or that version of iOS. From my expierence from iOS 4 to iOS 8 is that no one version of an iOS has actually impacted battery life on any of my devices the iPhone 4,5 and now my 6 in any noticeable way! This is all just from expierence and usage over the years. Once and awhile you have a stuck process that loops and eats up your cpu. Download a cpu monitoring app from the app store and check in on your cpu throughout the day and make sure it isn't acting up. If it is you need to reboot. I've been doing this since my iPhone 4 and that's how I make sure nothing's going weird and I have consistent battery life.
Sure new iOS versions knock out bugs and battery draining processes that might pop up once and awhile but usually it's the user who is making themselves think its the iOS that's killing their battery. Sometimes it could be in rare cases but from my expierence and common sense I've haven't seen a dramatic difference in battery life from one version of an iOS to the next. My two cents.