I always get confused by the nomenclature, so I'll say it this way: if you have a bare shaft that indicates too weak, i.e. nock left for a RH shooter, and you build out the side plate, the nock left will decrease. Building out the side plate affects other things too, like POI, and the bow was designed to be shot with a side plate thickness within a narrow range, so there may be better ways of doing this. However, if you think the bow needs a thicker side plate for other reasons, and the arrow is also too weak, then at least you're moving both things in the right direction.