Ok, think this way, if 8th brigade in Changxing do have J-20 now, then 2 of 3 brigades heritaged from the previous 3rd devision have got the J-20...
2nd devision was called "南霸天“, which was also the first three troops (among 1st and 3rd devision) to get Su-27SK beack then, OK, prestige might be overrated, but they certainly have some power at least
Let's put it this way -- it is entirely reasonable and logical that 6th brigade is not receiving J-20s right now, and instead getting converted or augmented with other modern Flanker types.