Why are Fullscreen Apps Inconsistent?

Has anyone else noticed that when you show the menubar in some Fullscreen Apps, that the animation isn't the same?

Example: Open iTunes and compare the animation to Safari when you move your mouse to the top of the screen. The top bar of Safari slides down with the Menu Bar, but not in iTunes.

It's a small thing and probably shouldn't bother me, but it does. Is anyone else experiencing this?