I agree with @SinoAmericanCW that both the Shenyang and Chengdu craft are supplements. If the Shenyang is meant to replace the J-35, the J-35 would get, what, a decade of relevance? It is far more likely that the J-36 and this are considerably more expensive than J-35 and J-20, especially with J-36's 3 engines. And there are still changes being made to the J-20.This one could be the replacement for J-35, while J-36 could be replacement for J20.