This sounds correct to me. I liken the noise to that of a wind up toy on some of the gears, others are virtually silent. After looking at the cut away view of the hub, there are so many gears going around I expect some noise.
When I stop pedaling the noise from the 'free wheel' depends on the gear I am in, again I do not worry about it.
Mine has done about 1500 miles.
regards
paul