Off to footy but just briefly. Qantas do some risk assessments. If the Engineering change they want is not endorsed, they find someone who will sign off on a new risk assessment and then deem the first person who rejected the change as a troublemaker and their career is over. This is how Qantas operate.
AMM says to check oil every 24 hours unless otherwise amended in an operator's System of Maintenance. The other option is there for airlines who don't fly their aircraft as much but Qantas take it literally to mean "if we can find some buffoon in CASA to sign off" it will be ok. There are lots of buffoons at CASA and of course many good people also.