After tower hours, overhead Rockhampton base of Class C is also down to 4500'. Nightly DHC8s, E-Jets and King Airs are given limited time to negotiate traffic, depart and ask for clearance prior to entering controlled airspace.
It probably causes more of a drama for ATC than the aircraft, but still the practice is non-standard and causes unnecessary problems.
Rumour has it that this is talk of changing it back to the standard J curve base of class E ie 8500', but it is yet to happen.