While I'd love to know what the repair person said, I would probably take it with a grain of salt until and unless there is any official statement from Nikon (not holding breath).
I would encourage anyone with this issue to learn how to do a wet cleaning themselves using Sensor Swabs and Eclipse fluid. It's not hard to do, but does take a little practice until you can do it efficiently. Until then, you may use up two or more swabs per cleaning, which is still less expensive than shipping and paying for cleaning. And, much more convenient.
One caveat, it's called a "wet" cleaning, but don't oversaturate the cleaning swabs, or you're more likely to leave solvent streaks. Maybe two or three drops of fluid on the cleaning edge, and give a few seconds for the fluid to spread evenly. Liken it to cleaning a window--a wet cloth will leave streaks, a damp cloth will not. I don't use a sensor loupe to determine cleaning efficiency, I just take a follow-up test shot and repeat cleaning if necessary.
Another thought. Some users have used unusual tone curves to make the dust more visible. While that's useful to monitor the condition, I, myself, wouldn't repeat a wet cleaning until spots showed up at more realistic settings and resolutions.