Nate, the technical name for this kind of system is called Mystery Progressive. MP's come in both stand alone and linked machines. In the case of Stations it is an extreme example of linked machines because all the machines in the casino are linked together on the progressive.
MP's come in a myriad of configurations but the most common MP's you see today are stand alones with one meter starting at $25 and must hit by $50, and another meter starting at $250 and must hit by $500.
This is my take on how they work which I developed the first time I encountered MP's...which was at the Mandalay Bay opening. Those banks of machines were billed as the "Lucky Coin Bonus System" and just the name alone was a big clue to me. To me "Lucky Coin" meant you didn't have to hit a line pay you just had to bet the coin number that would trigger the progressive.
So this is just a simple example of how I think they work. It's a stand alone penny machine, the meter resets to $9 and must hit by $10. The coin-in meter runs at 1% so $1 in action moves the meter up a penny. You are betting $1 per spin. At the $9 reset an RNG randomly selects coin number 476.
When you are betting $1 you are betting a block of 100 pennies.
You make the spin and the MP is not awarded because the lucky coin is not in the block of coins from 1 to 100. The meter moves up to $9.01.
You make another spin, the MP is not awarded because the lucky coin is not in the block of coins numbered from 101 to 200. The meter moves up to $9.02.
You make another spin and the MP is not awarded because the lucky coin number is not in the block of coins from 301 to 400. The meter moves up to $9.03.
On the next spin you are betting coin numbers 401 through 500 and the MP is awarded because coin number 476 is in that block of coins.
More on this later....I have things to do today.
