I would expect the job wasn't just "we'll pay you drive around non-stop for 9 hours/day". I bet it was probably more like "use this car for your commute and stuff, but be sure to have it up to 6km in X weeks" or something like that.
It would probably take a long time to run up 6k on a dyno, completely occupying that dyno for just one car. Doubt that would have been worth the cost of one (or multiple) dynos.
straight to gel