Yeah I think you got something there. Groups 2 and 3 if combined is the first of the larger boarding groups. Groups 2 and 3 will include all of the bundle buyers.

Nevertheless, after group 3 the gate area is still very crowded and nobody left has a carryon. Group 4 is the credit card holders paying revenue to Barclays with a cut to Frontier.

Even on full flights, most seats are still unassigned until T-24. The Frontier customer is now conditioned to flying with a backpack, no drinks, no seat assignment, and no wifi.
I'm shocked Frontier somehow collects $110 per passenger when loads are 70%. Once the taxes, employees, rent, and aircraft maintenance are paid, there is nothing left at $110 all-in.

The 20% load factor flights could be repositioning flights as part of daily expenses since Frontier parks 90% of the planes at the hubs from late evening to early morning except the 10% for quick turns. Frontier would otherwise never keep 20% load factor flights. That's when the $19 and $29 fares to/from hubs show up I think.