What's the final score?

[John Robertson]

In a game I was working last night, the score was 5-5 in the bottom of the seventh inning. A batter hit a three-run homer over the left field fence to win the game.

Softball Canada's rules say the game is over when the winning run scores. (No exception is given for a "walkoff home run" where more runs than needed to win the game are scored. Thus, very technically, the final score should be 6-5.) However, common practise seems to indicate the score is recorded as 8-5. This is really nitpicky--and it's more of the scorekeeper's domain--but it could affect a tournament in which runs for and against affect the standings.

How would this be scored in the good old U. S. of A.?