20% per hour battery drain with light useage. Normal?

[starstreak]

Maybe it's me and old age. But if I have to adjust brightness to less than 50% and I'm not in a dark room, just to get battery time that matches closer to specs is wrong. So I live with 50% and it tends to be bright enough.
It's like cell phones that claim 5 days of average use. (Disclaimer: brightness set to 10%, wifi on/cellular off/BT off, internet use set to 30mins a day) Or something stupid like that is wrong.