As long as you are SURE that the lack of hook is caused by the lanes having a heavier oil pattern than before, then a surface change would be beneficial. Especially since you state that you have already moved your shot around a bit looking for more friction. You want to do it in small steps. First step would be to remove that factory shine/polish. A white scotch-brite pad would work, or really any smoother grit scotchbrite pad would do the trick. Just make the ball a bit duller and you should see increased performance on oil. IF that does the trick, you're all set. If not, maybe the next step would be some 800 or 1000 grit sandpaper (wet sand the ball). You shouldn't have to go any rougher than that. If you need more than that you could do it with more grit, but why? Pick up a used or new particle ball and keep your Inferno for those medium shots.