Fishers usually does compete in Tier I. The schedule we received listed Large, Small, and Festival Divisions. Fishers was the only school listed in Festival which is represented by Tier III up above. I imagine it was their director's choice.
I mean someone from Fishers could surely share more. It might be the director's choice or it could be a host of other variables. Although, it really isn't uncommon for a director to request comments only, perform in exhibition, or compete down a level their first time out in competition - I've seen this play out across the show choir circuit. It looks like Fishers has a new director this season as well, so it might just be part of the transition/educational process.