I wonder why ducted systems were part of the requirements, is it because it's just aimed at the USA and then mostly at adoptability for existing systems (which seems to be ducted mostly)? I only have anecdotal experience and no numbers to back that up, but it's the only reason I can come up with that would put such a restriction in place.

I'd say rip the ducts out and just use split systems but I imagine other people have thought about that and figured it's not the best way to go. (or at last not in the US)