Dingbatt: My round trip commute to work is 70km so that alone accounts for 350km. I would say it is more likely that timmay's vehicle(s) probably use more like 9-11l/100km around town like our two do.
Ha-ha, my wife and I do a 7km round trip to work. We work at the same place but different hours. Anyway, we do 15L/100km as the cars never properly get to temperature except the weekend. We go about a month on a tank each including both the kid's sports and stuff, but that is 60L and 75L tanks. Move closer to work!