inaccurate manufacturers information

drive now my third toyota.currently avensis bj.11/03 2.4 with a hundred-and-a-half hp automatic transmission. when buying I was assured that the loader would only swallow max.10 l in urban traffic. think comes to just under 13 l. can that be ???? is also not a heizer or something usually normal and forward looking where the consumption? someone knows a advice or has experienced similar things.