The slot machines have a computer chip in them that determines the pay back percentage. These are preset. In order for a casino to change the pay back, they would have to change the chip. It is time consuming and the chips are very expensive. With regulation and the fact that the chip is preset with odds of payout means that this is not really an option a legitimate casino would even consider
Although the laws of probability dictate that the longer a machine is played the closer it gets to paying off a jackpot, it is equally likely that a jackpot could hit at any time including the next spin There is no way to determine if a machine is due to hit. Each spin is a random occurrence and has no bearing on what has happened previously. Don’t ever play more than you should because of this common misconception if you do chances are you will spend more money on a futile quest.
The RNG generates a number for each spin. The number corresponds to the symbols on the Reel. There can be hundreds of Virtual stops on each wheel even though you only see a few symbols. For example you may see 20 symbols on each wheel of a three-reel machine. You figure 20 x 20 x 20 = 8,000 combinations and your chance of hitting the jackpot is 1 in 8000. In reality the computer chip may program 256 stops for each wheel which makes the odds 256 x 256 x 256 =16,777,216 combinations. Being able to generate millions of combinations is the reason that slots can offer such large payouts as the chances of hitting them are quite small.