PLAN become a real "blue water navy". "Brown water" operations are past.That is actually an US Navy doctrine because they deploy their ships at far away regions that need long travel time from base to reach their patrol station, 3 ships is the minimum number they need to ensure there is always 1 ship doing patrolling.
China's navy defense is regional, the operational areas would be relatively near to their bases. They can have all ships in action as in MH370 search operation where they deployed all 3 type 071 in South Indian Ocean at the same time. The total number of type 071 in service then was three.
Patrol stations for PLAN are mainly located in Yellow Sea, East China Sea, South China Sea and they also have convoy escorts at Gulf of Aden.
The convoy escort mission in Gulf of Aden, due to its distance from China, does require the format of 1 ship (flotilla) on station, 1 ship (flotilla) on the way and 1 ship (flotilla) in base.
Operations in the scs near landing strips don't need LHDs.
The convoy escort mission in Gulf of Aden is the blue print for future operations in UN-Missions and at the maritime "silk road" to Africa and more.
075 LHD could be the backbone of those "blue water" missions