To admit You are wrong in either the whole story or with the simple designations:
To start with no AL-31 or WS-10 is interchangable between a Flanker and a J-10 since the Flankers need the gear-box mounted on to of the engine and the J-10 on the bottom. That's the reason why the AL-31F became the AL-31FN for the J.-10A.
As such if the J-11B uses the WS-10A no J-10 can use this engine ... and therefore the WS-10B was developed:
This engine however can not be used by any Flanker version and so either this J-10B-TH-version is not called WS-10B or the new TH with these black nozzles can not be a WS-10B.
Even more if You say:
... then this can't simply be !
Deino