When these slots first started a programer explained to me that they were NOT random, that the slot was set to pay off with the "random " jackpot on a certain spin number and it did not matter if players were spinning for .01 or 5.00 per spin.
The reason you see the counter spinning abnormally fast or resetting itself is that it is estimateing how many spins a player is playing so when there is a player playing 5.00 spin the counter starts flying, but when they stop it takes a few seconds for the jackpot reset itself to the correct amount.
As far as setting the payout %, it has nothing to do with the random jackpot, but the casinos are able to bank together a number of the games together to form a single random jackpot that will be larger than if each machine was random on its own.
I have seen players hit the random jackpot on the first spin or after hours of play, and have seen it hit for .01 and for the 5.00 spin.
I used to work for RTG, as a software developer, and I worked directly on the Real Series slots.
There is no magic spin number for the jackpot to pay off. Each spin is a completely independent event. Past spins have no impact at all on what the current or future spins will be.
Regardless of what you have heard or haven't heard up till now, the random jackpot "chance" of hitting is the same
per dollar wagered. That is the key.
To say it mathematically, playing 100 spins at $1 a spin has the same chance of hitting the jackpot as a single spin of $100 (long run).
So you aren't "missing out" on anything by playing lower stakes. And you aren't "gaining" anything by playing higher stakes.
The reason is a fixed % of each dollar wagered goes to feed the jackpot, regardless of how it was wagered.
Also the slots are truly video slots. Electronic representation of the "physical wheels" exist and for each spin the wheel stops are generated. Each stop on each wheel is equally likely. The way a payout % is achieved is by what symbols are on what wheels in what quantities. When set to a lower payout % the wheel(s) might have fewer "good" symbols and/or more "lesser" symbols.
Also, it should be noted the wheels are not necessarily uniform. Wheel 1 could have 32 symbols, wheel 2 could have 29, wheel 3 could have 37, and so forth.
It's very hard to spot changes in the wheels from payout % to payout% due to the fact you only need to make a minimal change to affect the %. Changing a high symbol to a low symbol on a single wheel or two very well might be the only change.