While I honestly believe you, there are two things going on. 9200 to 9400mAh is about 2% difference. Getting 15hrs extra is not much help without a reference. By my calcs, that battery is lasting 675hrs (28.5 days), so getting 15hrs extra, while impressive, isn't that much considering the scope of things. OR More likely, the previous battery was on it's way out, and replacing it with brand new fresh cells gave you the extra power that you've been missing. So while a fraction of that extra time was due to extra capacity, most of it was due to a new battery. All else equal, the battery in the GNex is a 6% increase, and should last 6% longer (eg 24hrs vs. 25.44hrs). But the LTE radio does take more power, so I expect it to be a wash to the GSM version.