The GM lounge benefit for Asian GM and PM used to extend to all partner airlines. So no use of partner airlines lounge. No SC when on a domestic itinerary. No SC when traveling on a different airline.
I have contacted DL on this. They won't acknowledge a change or give a reason for the change. All they will say is
"you should have received a letter in your 2011 Gold Medallion credentials kit that notes that you were granted SkyTeam Elite Plus status, which includes complimentary access to the lounges on an international itinerary."
DL apparently have not even told their staff in Asia. When I asked the elite line in Tokyo about this, they insisted there had been no change. When I asked how the staff at the lounges would know if there was nothing noted on the card, they just said they could check the address on file and see you were an Asian resident.