Old Akro,
Part of th e "problem" is that CASA and AsA (whether deliberately or otherwise I will leave to you) "confuse" cost/benefit justification and cost/effectiveness analysis, two different animals.
As your figures show, it is very cost effective for AsA, as for cost/benefit --- a joke in very poor taste, this without regard to the very doubtful "savings". Something called "proponent bias" is very evident.
Given the limited IFR traffic below FL 290, it is very difficult to show any cost savings to operators from the theoretically available reduced separation standards available with ADS-B OUT, likewise with reduced vertical separation, it is very hard to show real savings versus ausep standards.
Tootle pip!!