If it's not feasible to flatten and/or level the bottom of the billet in the area of the splice, or I just don't feel like messing with it, I clamp it to a short piece of 3" steel angle, wedging it as needed to hold it in alignment with the saw blade, and overhanging the angle so the saw blade doesn't contact it. Then the angle stays perfectly flat to on the saw table and all cuts will be in the same plane.