Yeah, I thought that exception only applied when the starter failed to go 5. But the link you provided is clear.
Still, last night's case was at the very borderline of where that exception is intended. The provided link gave a much worse example as the intent.
All in all, I think it's fine, as long as it's consistently applied, and it is an edge case anyway. W-L record for relievers is even less reliable as an indicator than it is for starters in the modern game.