Short visit in Shanghai - and then to Manilla

We are two danish retired peoble, and we are going to visit our son, daughter-in-law and our grandchild in Shanghai. We expect to obtain a 30 days visa from CVSC in Copenhagen.
We have E-ticket from CPH to Shanghai with SAS . The day after arival Shanghai we have E-tickets from Shanghai to Manilla, so we need a 72 hour transit for the entrence the day we arrive from CPH.
Our 30 day entry permit from the application service center is going to be used when we come back from Manilla til Shanghai. Will it give us problems in the airport? Do you have a good advice for us?

Kindly regards from Jacob Iskov, DK-7140 Stouby