That's a very valid point. I did consider that but wanted to post here and see if others were experiencing the same issue.
It's tough to get accurate info though. As soon as the thread pops up, people start thinking, and decide they have the same issue. Did you ever look at usage times under settings? If so, you can get a rough comparison. Even so, it's not terribly accurate unless you are doing the same exact things on the 5 as you did with the 4.