Ask Smithy Xtra Mitsu Pajero diesel service

Part of the 5-year warranty deal on my 2010 NT Mitsubishi Pajero diesel is that it had to be serviced by a Mitsubishi dealer at least once a year. I am fine with that, but at the January service they told me it needed to be serviced once every six months. As the car will do around 10,000 km per year, am I being gouged for two services per year, or are they necessary?