I have noticed since I jailbreaked that the usage & standby time no longer works. After it fully charges it shows 0 minutes for both but then when I recheck it, it disappears & shows the - for both. Wondering if this has happened to anyone else?
This has always happened. Like everyone said, if you respring, the device loses track of usage time. You must remember not to respring if you want to track usage time for the entire use of a battery cycle.