Sorry, worded the thread incorrectly. Of course it's not the DCT service, but simply the 1200 mile service.
I did check the service ticket before posting, and the service appears to have been done correctly, with an oil change using the recommened oil, oil filter change, and differential oil change, again, using the correct fluid. No trans fluid change. Yes I read about the problems in changing the DCT fluid, so checked that right away. No air filter change as somebody suggested.
I did search the forums here and elsewhere extensively, and saw some similar cases, but nothing after the 1200 mile service; some suggested a belt, somebody spilled coolant on a belt and that gave a high pitched whine, somebody said alternator.
I agree that it doesn't seem like the transmission as the whine occurs while revving in neutral, again starting at about 1500 rpms.
It's going back tomorrow as for some reason the seat memory buttons no longer work, so I'll have them try to figure out this annoying whine. Driving me crazy!