Quoted from Pinny-Lane:Didn't find a good thread on this upon searching.
Data East Jurassic Park pin
Sometimes the machine decides to start increasing the extra ball values and we can't figure out why. After scoping the manual we still have no idea why it does it. We've gone over all the menu options... nothing.
Recently reset the high scores, I got a new one yesterday and it went on a rampage, upping the extra ball value at every game afterward.
Are we missing something obvious?
It sounds like you have replay set to award extra ball instead of a free game, try setting adjustment 16 to NO to avoid the replay threshold creeping up.