Eben more they call it the fourth in the South!
Hmmm that's interesting, given your previous post:
CONFIRMED UNITS:
1. 176th … maybe gained later additional J-20 (II)
2. 172nd … gained later additional J-20 (II)
3. 9th (all J-20 (I))
4. 1st
5. 5th
6. 56th
7. 111th
8. 8th
9. 4th
10. 41st
11. 97th (all J-20 (II))
Then we have unconfirmed highly likely units:
12. 55th
13. 19th
… unconfirmed and questionable:
14. 54th (some reports claim it is now a J-16 unit)
… rumours only:
15. 131st
16. 2nd (more likely than 131st actually)
Of the first 13 units you list, 2 are FTTB (176th, 172nd), 2 are CTC (56th, 19th), 2 are NTC (1st, 55th), 3 are ETC (9th, 8th, 41st), 2 are STC (5th, 4th), 2 are WTC (111th, 97th). 54th AB is in ETC and 2nd AB is in NTC. So if there are 4 AB in the STC using J-20 that implies there is an unknown AB that switched to J-20 at some point that we don't even have rumors for. There are some units in STC that last we heard were flying outdated stuff like J-7s including 52nd, 53rd, and 132nd AB. I'd guess it's probably one of those 3.
Furthermore if there are 4 AB in STC flying J-20 I'd be fairly surprised if there weren't more AB in the other theater commands flying J-20. If 2nd AB is flying J-20 that brings the total in NTC to 3. I'd guess there's probably 1-2 more spread between CTC/ETC/WTC .