I have made a modification to the top wall. I played it multiple times and did not see the error so it "might" be fixed. There is so much going on in this code that when testing I see new stuff all the time that never happened before.
I removed the old version 0.6 and replaced it with the new code but with the same name. So 0.6 is the current version.
As for improving the ball, I'm don't think it will ever be like a real pinball machine. I don't think the Atari Video Pinball game was even close. Midnight Magic was closer but nothing like a real pin. The only video game I've seen even close is the Pinball Arcade and that is only if you have a pretty good PC so there is no lag. I will keep trying though. Currently space is extremely limited and I would be shocked to find a free variable