In response to it taking 7-10 days to work on your lens, you are right, it doesn't take that long. It probably takes a matter of hours, but they have a lot of other lenses, cameras, flashes, etc that they have to repair to. So it might take them 3 days to get to your lens, that's really all the 7-10 day estimates are, how long they expect it to take to get to your lens.
As for that time frame being standard, that depends. If you are the average consumer sending in equipment, I would say yes it is standard. If you are a belong to the "Pro" club with Nikon (not sure what it is called, it is CPS for Canon), then it usually takes 2-4 days from my experience.