Good point. Even the ATO issues binding rulings, lots of them. Why not CASA?
I once had to deal with six R&D investment syndicates - about $60m. Each one was supported by at least one private ATO ruling and then there were the public ATO rulings as well. They all had to be legally consistent too.
Things like what the phrase “for the benefit of the Australian economy” meant in legislation were spelled out in an ATO binding ruling.