You're just saying it is meaningless because you haven't got an argument. IT'S NOT CLEAR! That much is obvious. And if it is not clear, the lawsuit won't have any chance to survive in court. Like I said before it is DOA.
Lawyers find myriad ways to milk money from clients and I suspect this is just one more. As I said this is a minor skirmish that will go nowhere but cause distraction and create false expectations.
How to you suppose that the premium assistance credit amount of the taxpayer is the lesser of their premium under (A) [explicitly specified as a state exchange under 1311], or (B) [which you claim includes federal plans]? Is the taxpayer in both a state and federal exchange and whichever is the lesser premium applies?
If your claim that 36B(b)(2)(B) includes federal exchanges is correct, then 36B(b)(2)(A) must also include federal exchanges, something it explicitly does not do. Therefor 36B(b)(2)(B) must necessarily also refer to Exchanges established by the State under 1311, otherwise 36B(b)(2) would be meaningless because a taxpayer can not be enrolled in both a state and federal exchange and whichever is the lesser premium applies.