I had my D600 cleaned and inspected a few weeks ago at my local Nikon authorized repair center. They charged $45 for the cleaning and I thought it was well worth it to also have it inspected before the one-year warranty ran out. Glad to find out I have an oil-free model. The other day I received a check from Nikon for $36.42, sent to me with no explanation for why it was sent. Has anyone else received a check from Nikon after a D600 sensor cleaning at an authorized service center?