According to HKFA, ?? (??), was credited under ???? = Zao di cang shi = Hidden torsos and
Wong Chung (4) / (??) is not credited anyhwere at all.

In HKMDB, Wong Chung (4) / (??) is credited under story 3) but Wong Chung (1) / (??) is not credited anywhere at all.

Cd there be a mixed up?

It was my error. Sorry. Fixed.

Added the original credits for individual stories

http://hkmdb.com/db/movies/credits.mhtml?id=5668&display_set=eng