I think you are wrong as the first line in the AD clearly states that the AD is applicable to aircraft maintained under CAR 42B which is the CASA maintenance schedule. So as That Chinese Fella said it all comes back to the Log Book Statement and what system is applicable to that particular aircraft.
If you are not maintaining to the CASA Maintenance schedule then you will most likley be maintaining your aircraft manufactures schedule, most manufacturers require oil/filter to be serviced as per the engine manufactures requirements so you are back to say 50Hr/4Mth for example
You could be on your own system of maintenace approved by CASA however they are nearly always going to use either the CASA schedule or Mfr's schedule as a Minimmum when approving your system.
End of the day, the cheapest parts you can put on/in your engine is OIL FILTER and the FUEL