I have been studying the 'J-11B photos' released on Internet recently.
I have a theory: the aircraft shown in the photo may not be J-11B, it is a variant fitted with a Chinese-made avionics, but still with old AL-31F engine.
So far I haven't heard any concrete evidence showing aircraft powered by WS-10A is in service. From the photo we can see this new J-11 variant is already in operational service, therefore it may still be fitted with AL-31F.
Still, a big step forward for the aircraft to be able to fire PL-12 and PL-8
There are certain advantages not to use the WS-10A at all. First the advantage of using a local engine is kind of moot, and rather symbolic. Only to say it's Made in China and tactically, it has no significance. Developing an indigenous engine comes in handy when you are facing a possible boycott from your suppliers. But the opposite is in this case, since your supplier is dying to sell you, willing to give you good prices and the best technology.
Second, to introduce WS-10A means an entirely new system of logistical infrastructure has to be introduced for this engine. That means training of technicians, a new maintenance regimen, inventory of parts, distribution system and so on. Whereas for the AL-31F, you alrready have such a structure. In the end, its only more inconvenient for the PLAAF.
Third. Concept of WS-10 arose in the eighties when China and the Soviet Union is still in a faceoff. Even then after that China still distrusts Russia and wonders if a long term alliance or relationship can be maintained as both do not trust each other. So if Russia happens to embargo China, China can fully turn both J-11 and J-10 indigenous and not be reliant on Russia. However, in 2006, the geopolitics have changed, their relationship has more than sustained into an alliance. At the same time, China is in need now of Russia's oil and mineral resources. and needs to be in the good side of Putin. Also helps to release those RD-93s for Pakistan second export. But nonetheless, purchases from Russia also serve as a political tool, they can dual role as cards to help get better access to Siberian resources.