Toyota Kluger 2010: Over-servicing?

When my 2010 Toyota Kluger was in for its $170 fixed price 20,000 km service I was called to the service desk and advised that it was told that the fuel injectors needed a service for an additional $170. I felt that due to the low mileage and the premium fuel that I had been using this was a case of over -servicing to extract a few more dollars for their work. The service book only recommends that the fuel filters be changed at 48 months or 80,000 km. Surely this would indicate that Toyota expect the fuel system to be still functioning efficiently at this stage in the cars life. Appreciate your thoughts.