The cannon inserts do actually do something. It's just hard to tell with factory settings. It annoyed me that my first ramp shot was always a cannon shot for the song jackpot right off the bat not even giving me enough time to build the jackpot. So I turned that crap off. Now I have to light the "fire" inserts 4 times, this lights the first cannon insert, indicating the cannon is ready to load for jackpot collect. But yes, it would be nice to have some code that put these to better use.