Not sure if I understand you here. Are you saying that the 9th Brigade has 3 groups of 10 J-20 planes?Point is as mentioned by others already, that both the 176th and 172nd are training units with - at least as it seems - only one Dadui of 10 J-20s each. Only the 9th AB at Wuhu seems to have a full complement of three and as such eventually even up to 30 J-20s, The 1st at Anshan IMO has for the moment only one.
As such I think there are realistically 2 training daduis and 4 frontline fighter daduis or up to 60 J-20s in service, but surely not 120 or as the SCMP claims 150.
Or that it *may have* 30 planes in the future but right now it doesn't?
Or that it may have 30 but right now we don't know how many it has?
If it indeed does have 30 planes, would that be the first and only occasion where a unit having planes larger than J10 has more than 24 planes? It was my impression that most of the large fighter brigades in PLAAF had 3 groups of 8 planes each. J-11 units have 24 planes, no? J-16 as well? Su-30 units had even fewer planes if I'm not mistaken...