Can somebody please advise if single entry will do for our itinerary?

Good day!
We are 4 coming to Guangzhou from Manila on May 13 and go to Hong Kong the following day via train.
Will stay in Hong Kong until May 16 and then go back to Guangzhou for our return flight to Manila.
I have applied for Visa already , single entry for all of us. I realized we might need double entry due to our travel to GZ-Hong Kong-GZ?