The "Advantage Page Visible Sportsbook" setting in Odds Assist Pro controls what sportsbooks are shown in the +EV Bets, Arbitrage Bets, Live Arbitrage Bets, Middles, and Moving Lines tools.
If you remove a sportsbook from this section in settings, they won't show in these tools, even if they are selected in the on-page filter.
Only remove sportsbooks here that you never want to see in these tools.
Say, for example, you don't like using Bally Bet. You can unselect them from this setting and they will never show in any of these tools.