Vickie

Hi everyone. Im new to this I have an aurion 2009 sportivo and love it. I get it serviced reasonably regularly and normally get anywhere from 9 - 11km per 100. I recently put new tyres on the car and have not gotten below 12km per 100. Im planning on a trip to qld and having it serviced when i get back. The guy at the tyre place said its the car not the tyres. Any ideas would be helpful