Vintage Pachinko machines have to be periodically refilled. Someone has to take all of the balls that have been played from the lower tray and pour them into the upper tray.

I can think of an easy way this could be eliminated. What if each time a player pulled the lever and fired a ball he was actually firing two? One ball would go up and onto the playing field as usual but the other would be on another track next to that one and would go up and into the upper tray.

Wouldn't this be possible or am I missing something?

Yes the player would have to work twice as hard but would this be noticeable?