My daughter bought a March 2012 Hyundai ix35 a few weeks ago with just under 13K miles. The sales person and the service book says services every 20k miles or biannually. When I asked regarding oil and filter change I was given the same advice. I know you get many similar questions such as this and I would think an oil change is overdue and should be done every 10K miles? Do you agree she should not wait until 20K miles?