That is a bit unusual. My engine would consume 1L every 4-6k km and I have no problem living with that. Do you track your car very often or do you drive real aggressively all the time? Those are the only 2 causes I can think of when a engine consumes so much oil over that mileage you have. Get the dealer to check it again and if not, visit another dealer. You always want to be safe than sorry.
Must stop eating..............