Even though CAO 20.2 refers you to AWB 28-002, according to the CASA web site AWB 28-002 was cancelled several years ago. The CASA web page now refers to CAAP 234-1 (1).
Civil Aviation Safety Authority - AWB 28 - Fuel systems
Imagine the paperwork if an operator was to be audited aand this type of mistake was found.
One rule for them and another for us.