That phone will not last 10 hours. When companies do those tests for battery life they do it with nothing on, no screen, no apps in the background, no mail, nothing. It's not even remotely similar to the usage that people will get in the real world.
... These battery tests are accurate, they are not battery tests for you playing while talking. I'm not sure what you are talking about. The tests are accurate, now if you want other battery tests, sure but the ones presented are accurate.