The article suggests a lack of understanding of:
- an "area" frequency i.e. FIA Flight Information Area;
- a high altitude ATC control frequency (which aren't normally the same);
The explanation in the NOTAM is a no brainer - the procedures are what should be used and have been for many years.
Whatever conflicting text has been in AIP since May 2013 was originated by CASA. It sounds like they either worded it poorly or got it wrong.