This subject was discussed at length by all the RAPACs in the late 90's.
There was a choice - At airfields / landing grounds / Farmer Joe's paddock etc that DO NOT have a promulgated CTAF with an associated frequency - ie: Not in ERSA;
Either you publish a frequency for use at such locations,
or
Use the area frequency.
The former was decided upon and in line with our comrades in North America it was called "MULTICOM" - In all cases the MULTICOM is 126.7.
Good airmanship suggests that the area frequency be monitored if you have two comms, but broadcasts should be made on the MULTICOM, unless there is a need to resolve a conflict (or whatever) on the area frequency. IFR ops would use those procedures common with any published CTAFs.
My guess is that the confusion in the CASA document relates to a lack of corporate history and/or understanding of the subject by the writer.