I wonder why the PLAN needs so many 904/As...
Hopefully it is the new larger AOR we've been predicting, but who knows.
Once the sixth 903A is commissioned within a year or so, and assuming the older 905s aren't retired, PLAN will have two 21,000 ton, two 20,500 ton, four 23,000 ton, and a single 37,000 ton AOR... coming to a total of 210,000+ tons worth of AOR.
From skimming over various navies on wiki, once the sixth 903A is done, PLAN will be fairly close with the RN's RFA fleet oilers and replenishment ships which comes to about the same number (two 31,500 tonners, two 16,200 tonners, one 34,000 tonner and four 37,000 tonners -- although these are to enter service from 2016 onwards).
So by early 2016, PLAN will likely tie with the RFA for second in terms of total AOR displacement, and ahead of (in no particular order...): Marine Nationale (four 18,000 tonners), JMSDF (two 25,000 tonners and three 15,000 tonners), Indian Navy (two 27,500 tonners, one 36,000 tonner, one 25,000 tonner) German Navy, (two 20,000 tonners, two 14,000 tonners) -- but of course even then, the PLAN will be very behind the USN's massive replenishment fleet that I won't even bother to try and tally.
PLAN can definitely benefit by commissioning a half dozen 40,000 ton AORs over the next decade, mostly to have them in place to support CSGs as the new aircraft carriers begin to enter service, and ESGs too as they have LHAs to join their LPDs.
But at present and in the foreseeable future, the PLAN will have quite a competitive AOR fleet. Their current 20,000+ ton AORs will also be useful in future to support forward deployed SAGs, while the 40,000 tonners can be left to support forward deployed CSGs or ESGs that will require more stores and fuel.