Huge difference and to be honest it's a complete mess
I understand your frustration. Half is ICAO, half FAA then a mixture of extra rules on top of everything (normally stuff which is just basic common sense) but have been incorporated into the rules.
If I could give any advice I would strongly urge you to get a Bob-Tait law book an start from scratch especially if your operation is IFR. Also the aircraft radio phraseology is much different too. E.g departure call from a class D aerodrome, and the order of content in a radio call.
Again yes you are banging your head against the wall
sifting though tonns of irrelevant garbarge with nothing to do with the information you want instead of looking precisely at one rule part and extracting the information easily
Again a law book will solve this and help you find where to look for it plus give reference to where you should be looking.
But if you are a CP you should know where to find all this stuff so I guess there is no easy way around it but it learn it of heart. AIP in Australia is pretty good if you have not already found it
Airservices Australia -<% = flying_aip_text %>
Best of luck!