If you have your hand on top of the ball like John Walsh and Robbie Bosco (as a junior. Did the opposite as a senior to protect his shoulder), you have a high release and pull the nose down. You get your hand under the ball, the nose can get up in the air and sail.
Hand under the ball is usually bad habit holdover from youth when the qbs hand wasn't big enough.
Magnum's hand position on the ball looks ok. The only issue is the low release and opportunity to knock the ball down or tip it up in the air. I don't remember him having a problem with passes sailing.