for what its worth, I've done the same in asia before and did not encounter any problems. i did a PVG-PEK + PEK-ICN-NRT round trip and since i did not need to be at PEK on the way back, i basically skipped two legs (ICN-PEK-PVG) and replacing it by one direct back to PVG (ICN-PVG). all were on sky team airlines.