Recently there has been a move for reasons that remain unclear to change the Australian regulations to be totally compliant with the ICAO medical standards.
that is easy to explain. the age old "reference to a higher authority" it is used all the time to negate criticism.
CASA are nutters. just look at the volume of guff produced in the name of regulation. "ICAO" and "EASA" must be wonderful tools for the deflection of criticism.