If the Ishihara test is failed, a certificate will be offered restricted to day VFR only. If the applicant wants this restriction removed, they must pass one of the tests as per Part 67.
That is a failure by CASA to comply with the law. Pure and simple.
An applicant who passes any one of the tests in CASR 67.150(6) has demonstrated compliance with the colour perception standard. Full stop.
(Keep an eye on that website text, brissyp. I anticipate that it will magically change, shortly.)
It's obvious to me that Avmed has one too many zealots on a medical crusade, unhindered by mere trivialities like compliance with the law.
It's no wonder the AAT decisions are so simple.