And here is a clarification from
CASA's website:
All flight time during which the aircraft was controlled solely by reference to instruments may be recorded in the instrument 'Flight' column:
a) Time above overcast or at night in Visual Meteorological Conditions (VMC) is not counted as instrument flight;
b) In actual or simulated instrument conditions, only the pilot manipulating the controls or providing input to the auto-pilot may log all flight time as instrument flight;
c) A flight conducted on an Instrument Flight Rules (IFR) flight plan is not to be counted as instrument flight unless flying in IMC;
d) Instrument approaches are to be credited to the pilot (pilots, in the case of an airborne radar approach) manipulating the controls or providing input to the auto-pilot during the approach.
In my airline it is normal procedure for pilot flying to just log 30 mins per sector, mainly because no-one really cares about this largely meaningless statistic, and it'll be reasonably close on average.