Maybe I'm wrong but i think en banc or Supreme Court hearing this at this stage is a longshot. I think Frosh will tilt at the windmill because he has to, but 1- the court's own precedent seems to require this result;2-its only a remand for more fact finding. The full court can let this percolate more before they take it. Plus, the dissent is not very persuasive.
Persuasive or not, the case has been remanded to a court that's historically receptive to IS. And Frosh is betting that the majority of En Banc judges will see things that way as well.