Your post is confusing as fuck. Someone lies about their work hours but only lies sometimes and mixes up the days? Well I'd say its simply to avoid being caught..

Say a person is creative with their time keeping at work and likely does not put in the reported time and/or works from an unauthorized location. Why would they bother to be honest sometimes in an environment where no one who has any authority really knows if and when you come and go? For example, if you do this a little bit every week, why would you put in the time on some days where you normally would report creative hours?