It really hasn't been resolved. No one at DL is willing to admit that the decision was wrong regarding my not being allowed to board with my TWOV compliant itinerary and ticket and it doesn't seem to be possible to contact anyone at DL who can straighten out the problems with using TWOV on DL to China. DL simply waived the change fees on my ticket and kept my upgrade instruments attached to it, thus allowing me to rebook later to a different destination.