I asked on another forum site and got this as response
Assuming you get the 5 wins in the haunted house, I would take the key every time.
If you take the key, you get 400 treats for 8 wins, 130 treats for winning all 13 games, and 800 treats for winning 5 games of the haunted house. So for 13 games you get 1330 treats or 102.37 treats per game
If you don't take the key it's 400 treats for 8 wins, 200 treats instead of the key, and 80 treats for winning 8 games. That's a total of 680 treats for 8 games or 85 treats per game.
I asked on another forum site and got this as response
Assuming you get the 5 wins in the haunted house, I would take the key every time.
If you take the key, you get 400 treats for 8 wins, 130 treats for winning all 13 games, and 800 treats for winning 5 games of the haunted house. So for 13 games you get 1330 treats or 102.37 treats per game
If you don't take the key it's 400 treats for 8 wins, 200 treats instead of the key, and 80 treats for winning 8 games. That's a total of 680 treats for 8 games or 85 treats per game.