It is only in Norway that we guarantee the right timestamp on SMS. In other countries the SMS will get a time stamp from the operator that is used for interconnection to the recipients country. This will vary and could be in other time zones. If it is important to know when a message is generated this value must be added in the message text from the sender.
Messages sent from countries in the same time zone may get the wrong timestamp. The reason is that traffic is sent through other operators located in other time zones. This is normal as long as it is not agreed on forced direct routing.