Bustamante won 14 of the 17 games that involved one or more safeties.
Sometimes a safety has no immediate impact on winning or losing the game and sometimes it does. Looking for "immediate impact" --
So I'd tally that as a 9-3 games won result in Bustamante's favor on immediate impact of safeties.
- - Safeties good enough to win game on own next visit -- 5 by Bustamante, 3 by Bergman
- Safeties bad enough to lose game on opponent's next visit -- 0 by Bustamante, 4 by Bergman
So there you have it, that explains the margin. Thanks for your efforts!