A friend of mine recently went from an iPhone 6 to an iPhone 7 and is having much less battery life with the 7. The Apple store checked out the phone and said that since the 7's battery is smaller it doesn't last as long and that using data (like for calls), drains the battery faster. I'm having a hard time believing this. Apple specs show the 7 to have a much longer battery life across the board over the 6. So what gives?