Does the iPhone's "usage" erase after sync?

Does the iPhone 3G S "usage" disappear and go blank after you sync or charge for a minute? I'm at 60% and have has awesome battery usage but when I did a quick syn on iTunes it just went to "Usage -" and "Standby -" and all my times went away. Normal?

 

hmm, well if anyone doesn't mind plugging it in the charger or for a quick iTunes sync and let me know if it does this to you then I would appreciate it.

Basically when I connect it to itunes via usb and the unplug it after a sync of a song or application then my usage just disappears.