Hopefully one of the official ford techs (they are Ford employees, right?) can answer my question.

I have a 2013 GT Premium, which is used primarily on weekends and for pleasure driving. It's not a daily driver. It's almost exclusively driven in highway conditions with minimal idling, etc. It get's garaged and mostly unused between Dec and Feb due to frequent snow/ice conditions that I would rather not drive it on.

In 20 months of owing it, I have racked up only 8,000mi. I had the oil changed @ 2400 and @ 4600 miles. Both at 6 month intervals. This is drastically below what the manual says (5-10,000) and what the oil life monitor tells me.

I always put full synthetic in the vehicle (Motorcraft).

Common sense tells me I am wasting money, but I am concerned about my warranty and about my extended service plan. The ESP says that the plan will be void if I don't follow the manufacturers schedule, or if the manufacturer does not state a schedule the minimum is every 6 months or 5,000 miles.

My dealer has told me not to worry about it -- the ESP only really cares about mileage and that since I am using synthetic oil I can easily go 8 months between changes.

What is the official word from Ford service and Ford ESP? Will my warranty and ESP be voided if I follow the manual and oil sensor information (meaning I would be changing oil at most 1/year). Where/how can I get an official, in writing response?