I think it depends on the person. I usually keep my carbs in the ~30-40 gram range(OWL), but once every few weeks I eat someting that is higher in carbs than it shold be. I am still losing weight. Mind you I don't go nuts, and I keep away from sugar altogether. I am also not watching the scale anymore, if you watch it daily you go nuts. i check the scale about once a month.

Your mileage may vary, but I think once and a while some extra sensible carbs don't hurt. All depens on the person though.