Is it possible that China's export versions could be of a high quality (and thus range) than domestic ones, even this does not make realist rational sense?
Immensely doubtful. In some rare cases the the Chinese defence industry have exported more advanced and more capable weapons than what they were initially inducting at the time, but this overwhelmingly tends to be ground/army weapons like AFVs or artillery, and rockets, rather than more strategic and advanced weapons like SAMs, AShMs and the like.
The bigger issue is why their report threw out 220 km when C-602 (export YJ-62) has been listed to have a range of 280km quite publicly for a number of years now, to comply with MTCR.
I could understand if the report listed 280km as they might consider that a more reliable number compared to the rumoured 400+ km we've known for a number of years now, but 220km?? It is such a random number I wonder if some unknowledgeable hack job of an analyst just threw it out there without consulting even a google search.
(Note, I haven't actually read the report, but if they did list 220km as YJ-62's range then all my above still holds)