I assume you are in Shanghai (or China) now? Take down the detailed fare construction of the flights you want on matrix.itasoftware. Go to a China Southern office, or the office of a local travel agent, and just have them punch it up and do the etickets. Should be replicatable. Looks like it is in the RMB 6100 range, all in. I doubt you will do better than that for a round-trip in August.

Be old-fashioned for a change. Sometimes technology costs us time and angst rather than saves us.