Hello @ ornbassar!
This is a very interesting question and I understand how the time on the logs might be a concern. I will be more than happy to provide you some information!
While you are able to manage your phone’s Date and Time Settings, your online history report displays the information, which is generated from our billing system and cannot be changed. This means, it is possible for the system to be located in a different time zone from where you are located. I do apologize for any inconvenience this might cause.
I hope you find this information helpful. Please let us know if you have any other questions.
Have a nice day!
Anabel, AT&T Community Specialist