Quoted from rotordave:
Competition mode does not turn off extra balls. In most games, it will align random awards so they are the same for each player.
The only way to turn off EBs is to go to the SPI menu option “extra balls” (the 5th option from memory) Turn them down to 0.
So, 2 steps for competition:
1/ turn off extra balls
2/ turn on Competition option (or Tournament, depending on game)
There is an easier way I actually learned from Josh Sharpe. Go to INSTALLS menu. Install NOVELTY, then install COMPETITION. Done!