Quickie
Colonel
What's underlying the 10:0 claim for the J-20? That's implying that the J-20 can carry 2 WVR missiles and 6 BVR missiles as a baseline, with 2 additional WVR or BVR missiles as well. See the F-22 and F-35 figures: they supposedly have a 8:1 and 4:1 ratio respectively when pitted against 4th (US) generation aircraft. That goes into my theory: the J-20 can, with LOAL missiles and the outside gird removed, carry 4 WVR missiles in its side bays. Alternately, the figures came from jamming 8 intermediate range WVR missiles into the main bays.
It could be more than one J-20 fighting a group of J-10 or J-11.