OP,
I hope you received your refund. When you enter your trip in TIMATIC via Sky team link using USA as departure point and destination country and Japan and China as transit points it displays the correct visa information.
Interestingly when searching on google flights for trips to China- there is a link for visa info:
http://travel.state.gov/content/pass...try/china.html
There is a paragraph
If Beijing Capital, Shanghai Pudong, Guangzhou Baiyun, Chengdu Shuangliu, Shenyang Taoxian, or Dalian Zhoushuizi airport is your international transit point, you may stay in mainland China for 72 hours without a Chinese visa if you have: a valid passport, a
visa for your third country destination, an onward plane ticket departing from the same airport, and you remain in the same municipality or province in which you entered
I wonder if that's where DL erroneous information comes from.
As I posted in recent thread my daughter made an error booking 72 TWOV route SIN- KUL- CTU (Air Asia) and CTU- PVG-OKJ (China Eastern) ( paid flights) and was
correctly denied boarding by Air Asia in SIN. However they agreed to check her in for first leg SIN-KUL which gave her time to come up with alternate route out of CTU. Prior to booking an award ticket using DL miles on CI (CTU-TPE-KIX )routing she had Air Asia GA in KUL ( who also checked with their supervisor or GS) double check and approve her new itinerary. No further issues with TWOV.