There is a difference between the navigation bar and the status bar. The confusing part is that it looks like one solid feature at the top of the screen, but the areas can actually be separated into two distinct views; a status bar and a navigation bar. The status bar spans from y=0 to y=20 points and the navigation bar spans from y=20 to y=64 points. So the navigation bar (which is where the page title and navigation buttons go) has a height of 44 points, but the status bar and navigation bar together have a total height of 64 points.
Here is a great resource that addresses this question along with a number of other sizing idiosyncrasies in iOS7: http://ivomynttinen.com/blog/the-ios-7-design-cheat-sheet/