We dont know if j16 regiments are modelled after su30 regiments. Perhaps operating 18 planes each.
IIRC, that was due to the limited number of Su-30s imported, not because of a change in PLANAF doctrine. Ideally, the Su-30 regiments will also have the full 24 aircraft. Since the J-16's numbers are not constrained by Russia and not subjected to FMS costs, it's most likely that J-16 regiments will get their full 24 plane's worth.