[St Charles Owl]

Here is another option:

Incorrect result Gamball -4
Incorrect result Bonus -2
Incorrect result -1
Correct result +1
Correct result Bonus +2
Correct result Gamball +4
Correct score +2
Correct score Bonus +4
Correct score Gamball +8

That would make it still worth playing the Gamball and not penalize those for getting other score right.