This is a throwback to when the military controlled all the avaition and airfields in PRC. In the beginning all airfields used QFE procedures. Increasingly however the airfields have been taken over by civilian authorities and companies and are now using QHN. To aid operators that were using QHN in the QFE environment Jepp introduced the conversion chart that I think you refer to.
This enabled crews to quickly convert a metric QFE clearance to QHN in feet and thus avoid the obvious errors in the heat of the moment.
Hongqiao is now a QNH airport along with Pudong ZSPD which would probably be your div airfield if you were going to Shanghai. From memory all the other airfields that an overseas operator would be allowed to file to in the Shanghai area are similarly QNH now.