I'm not surprised ATSB checked with CASA.
That means that CASA takes the view that AIP 80.3 is not the subject of a legally valid direction.
The fact that it remains in the AIP in its misleading mandatory terms, or has not been made mandatory by a valid supporting direction with consistent complementary guidance material, is, I am afraid, typical of the two and half ringed political circus that passes as your aviation regulators.