My understanding (which I am becoming less clear about) is that twin type ratings disappear under xxxx kg (to be determined, probably 5700 kg). It will be just like a SE rating. C441 & PC12 are both under 5700kg.
The logic is that above this weight is pretty much only RPT type aircraft which will be covered by the operators systems.
The real scandal is that less than 2 months out, CASA cannot provide clear guidance on some pretty basic questions.