[Faterson]

Theoretical battery life based on artificial tests, and battery life in actual usage, are two very different things, and will vary from user to user. Those charts don't really mean anything for any specific user; real-life experience may be completely different based on what a user typically does on the device, which varies from user to user. We've seen this over many years regarding battery life on laptops -- manufacturers typically overstate the laptops' battery life, to get better sales.

For example, I prefer to read in Night Mode (light font on all-black background), and for this reason alone, I'm likely to get better battery life out of my tablet than someone who prefers reading books in Day Mode. (Let alone someone who prefers watching HD videos or playing graphics-demanding games.)