does it matter if im being told to lie on my timesheet

I'm an exempt employee which means 8-5 mon -fri. But I often work 60-80 hours a week. My issue comes with we are forced to fill out a time sheet but we are forced to lie on our time sheets. We are never allowed to log more than 40 hours. I know it dosen't affect my pay but I would like official records of the time I put in. Is this legal or am I just being paranoid? My bossis no help and just keeps telling me I need to be a team player