Whats your usage patterns like?
Heavy gaming etc?
I believe this pattern is accurate for graphic intensive games.
I'm on a 6 and draining about 20%/hour when playing COC.
From my experience, it's actually relatively easy to get an exchange from Commcenter. Find some other problems such as dead pixel/yellowish screen tint if you really wanna get an exchange.
To be very frank , I don't play games at all.
What I do most is on whatsapp as I was chatting away with my friend.
That takes up like 41% .... Safari 10%
Sigh