RCT-991 - Father, guess which one is your daughter! Giant breast sisters 3P

The first couple doesn't have a 3P, and the second is less of a 3P and more of a father just alternating penetration between sisters (no fellatio either). The third couple does have a 3P. It's the typical Rocket-style plot where the daughters fear pregnancy but ultimately give in to pleasure. Personally, I wish all three couples had done a 3P. Couldn't they structure it so that if they get it right, it's a 'bonus chance' for incest, and if they get it wrong, it's a 'second chance' for incest?