Ah, the problem with common names.
Since Panaeolus subbalteatus and Psilocybe subaeruginosa both occur in Australia I think it would be best (as a matter of best practice and in order to avoid confusion) if the term "subs" would be used to refer to P. subbalteatus and the term "copper tops" be used to refer to P. subaeruginosa. Also to be taken into account is the fact that overseas the term "subs" has been taken to refer to P. subbalteatus for many years.