Personally, I have never liked the idea of buying onto an even number in a baseball total.
5-4, and you have a winner, but that extra run, is worth two if it goes to 5-5, and both bets would be toast.
A .45 swing is pretty substancial, for a half run.
I would need to know which game, for a complete oppinion, but as a general rule, I would take the extra money, over the extra half run, when it is that big.