Looking at the latest images..........it appears the 055 program is being given priority, in terms of effort in getting the vessels built. A bit like when the first 052D was outfitted very quickly, and actually joined the Chinese Navy, before the last two 052C's.
Also by building more than one at a time, i'am sure the Chinese are saving quite a bit of money, on their construction, which in turn means they can afford to build more in the future!
Anyway, overall its great to see so much activity at these Chinese naval shipyards!