Is it possible for time stamps to be wrong on cell phone bill?

scenerio: texts sent and received from my cell phone are not in question but the time stamps attached to them are which brings into question the content of said text messages. is it ever possible for the time stamps attached to text sent or recieved to be wrong on the bill. i have been told it is very unlikely but i maintain they are completely inaccurate. i have read and was told sometimes the time zones for either number can play a part but both sender and receiver are in the same time zone. also, conversation was in real time as far as sent and then relpy in regards to the on going conversation.