I wouldn't be so quick to say that, especially if it's Anandtech doing the test considering his methods and reporting are the least biased and most detailed around the net -
AnandTech | The Samsung Galaxy Note 4 Review (this seems to have been done before the battery life boosting update too). From my experience with Android phones, battery life is inconsistent even in the Note series. Just today Google Services ate a crap tonne of my battery life in the background for no reason, causing my usual 5 hour screen on time on my Note 3 to go down to 2.5 hours. And I wouldn't have believed the outrageous 7 hours screen on web surfing time of some xda note 3 users had I not personally done the same for mine.
The biggest factor in battery life for me is the signal strength. Android typically doesn't fare too well here. It seems to ramp up the antenna power way too much. When I was overseas, my S3 LTE lasted twice as long per charge as it did in Singapore, so the tests done on the Note 4 might have been similarly affected.
Also, 4G+ is sure to eat a tonne of battery. And the launcher of choice matters too. I was using Nova Launcher for the longest time until I did a battery life comparison between TouchWiz, Google Now Launcher, and Nova. My god Nova sucks battery. I got half the screen on time with Nova compared to TouchWiz.
Hmm crap. The itch to upgrade to the Note 4 just to check out the battery life is getting stronger. Even though there's absolutely nothing wrong with my Note 3. Ugh the pain of being a geek. >.<