No, not much difference. Unless I've missed something, the additional one year is an option for the club, not the player. If he does well in the initial three years like he's done in eight years here, then the one year will be rightly activated. If he doesn't do well, then he can be let go after the first three years.
Well every defender could have conceded many penalties in various games. Smalling is no exception, and the thing is, the objective referees who follow the damn rules without sentiments didn't deem them to be penalties, the same way VAR wouldn't deem them to be penalties. There's nothing lucky about it. Nothing really comes across as accurate when it is completely based on could have and could have.