The Rebar sizes in the pull down are US sizes i.e 3:40E how to change to other Rebar sizes i.e Australian Y16 or N16.
The Rebar sizes in ProConcrete shows as per current Rebar Code selected.
Open the Rebar Codes dialog (select icon in ProConcrete ribbon menu or select from drop menu ProStructures->Concrete->Rebar/Concrete Codes). Change it to your required one (review code units).
Change Rebar Code to AS3600: