Hi,
1. Can you send me the running configuration?
2. what is the timezone you ave defined?
3. Can you check the phone's configuration file and check the time-zone specified under it. Make sure you have specified the phone type under ephone and then reset the phone, you also can check by "show telephony tftp-binding " and looking for item of your phone "SEPxxxx.xml" , it contains the timezone setting for IP Phone.
4. Output of the following:
Show clock
Show ntp associations
At the same time check the time on the phones and see how much is the offset?
Aseem