After the announced payouts there's only $340 left for the remaining 28 players - don't see how they are keeping much at all since all those other folks apparently get something.
I think that "Full Field Payout" does not mean that everyone gets money back. I think it means that if the field is full, these are the top (or maybe only) payouts. I think the house is going to keep the remaining $340. Maybe $40 each for the next four and the house keeps $180.
Evidently it's not single elimination since 3-4 play off with $50 in the middle.