Think you are correct! One of those deals where your eyes cross from the jargon
Much like the 2×2 stack sets, the Bunch set is used to stress the defense, but in a different way. Anytime an offense aligns in a 3×1 set, it has the opportunity to go vertical and stress the defense. Versus a two-high scheme, the defense can gain a plus-one, but it is stressed versus four verticals. Single-high is able to load the box, but the pass distribution is the same and the defense loses a defender to the single receiver side. Most offenses do not run four verticals out of bunch sets because of the spacing. Instead, many rely on high-low concepts. In order to match up, and stay sound to the boundary, a defense treats the bunch much like it does a stack set. In the diagram below, a “Cold” call is needed to tell the Sam to apex the bunch and hold the curl. The Mike is allowed to stay in the box and hold the run. The CB is responsible for the first outside route, while the Sam is responsible for the first “in” route. The safety holds leverage over the bunch and protects the vertical. To the boundary, the safety and CB stay in quarters coverage allowing the safety to “rob” the curl and attack the run game weak. If spinning, it is best to press the Sam, and have the spinning safety hold the curl. The CB, who is outside the bunch set needs to work over the unit and hold any vertical. If the offense aligns the Bunch set tight to the box, the Sam must align outside the “on the ball” WR and press the outside shoulder. The CB aligns 3×3 off the outside man, holding the edge if there is an outside run play. Teams use the bunch to gain an advantage in the run game, especially is aligned to the box