I believe the basketball shot either misses or goes in depending on how many battles you've won. I believe the Ultimania states that if it's below a certain number, it misses. If you're over-levelled (having won a lot of battles), it bounces in off the backboard and ring. If you're 'just right' and somewhere in between, it goes straight in. I didn't really test it, but I'm pretty sure that during my low level/maximum Junction abuse runs, the ball never goes in and during my normal playthroughs, it occasionally goes in.