Pro Set League Rule Question

[efgamer]

Say that you are jamming a WR and have a LB just inside of the WR. After the snap you decide to slide the LB over and double jam the WR? Is this allowed? I have experimented with many variations of positions and you can actually get into questionable or unclear movements which result in the defense gaining a clear unfair advantage. Please give me a more precise definition of a defender movement. Thanks