I think it was @rbynaker who was first to point out that the new subsection required that "modified AGI" be figured without regard to the entire section, and not just the subsection.  I am not surprised that IRS has conceded so quickly, but I'm surprised that it's not yet Friday night.  

IMO that's summer work.  Possibly Fall.  Maybe even early Winter.

Except for changing filing status from MFJ to MFS.  Don't let those returns turn into pumpkins.