Plan for a result you cannot predict
96.51 percent is the RTP of Big Bass Bonanza 1000, and that number describes the return over a very large number of spins, not one session. How often the bonus round comes is not known in advance. The result of any single session is random, whatever the RTP.
The 5x3 grid of Big Bass Bonanza 1000 is offered with one listed RTP. Which RTP version runs in this lobby is shown only in the game rules, so check there first. Read that line before you set a bet, since the RTP sets the long-run return on every A$100 staked.
20,000 times the bet is the highest win this slot can pay, and it is reached very rarely. Hitting that ceiling depends on chance in the bonus features, so no player can plan around it. The figure states the limit, not what a session will return.