I am guessing that C5 knew how popular Aaron was and that he had it in the bag by the voting come the time they came up with the money twist to deprive him of all the prize money, that also makes me think Aaron was very popular and won by a hefty margin also
I expect he won by a hefty margin each time he was up for eviction
Hence the twist like the crypt to try and help Jay make the final by adding more housemates to the mix.