Forget the RNG. It's PROGRAMING

[kjmema]

This is an interesting article which was in the  Casino City Times

The RNG is a mathematical function in the programming of a slot machine that generates a series of numbers. When you press the Spin button, the program retrieves the most recently generated number to determine the outcome. So, the RNG doesn't read numbers, it generates them.
Now, a casino could license three or more payback programs (which are really just virtual reel layouts) for each machine. But these programs aren't free. I don't kow the pricing model for downloadable games -- and each casino company probably strikes its own deal -- but new chipsets were about $1,500 each a few years ago. The machines have to be able to earn enough additional money to pay for the additional programs.
Another cost of changing a machine's payback is reporting the change to the state. All of the states want to ensure that they are getting their fair share of casino profits, so they want to know the long-term paybacks of all the machines on the casino's floor.
The requirement in Nevada is that a machine be idle for four minutes before and after a configuration change and that it display a message while its configuration is being changed. The requirement exists to prevent a machine from being changed while it is being played. Even if multiple payback programs could be sent to a machine once and scheduled to take effect at certain times, the machines would still have to be idle before and after the change.
Casinos can change the paybacks on their machines, so your chances of winning on a slot machine are not necessarily the same every time you set foot in the casino. A 95% payback machine is a 95% payback machine 100% of the time. If you change the virtual reel layout, and thus the long-term payback, it is no longer a 95% payback machine.
Downloadable games has made it much easier for casinos to reprogram their next generation slot machines. The fact remains, however, that it still does not make economic sense for a casino to license additional payback programs just for use on a few days a month.
I agree with you, however, that it is not about the RNG, it's about the programming, i.e., the virtual reel layout. Players put too much emphasis on the RNG, even though the numbers from it are just raw material. What the machine does with the numbers is the interesting part.
It's not about the canvas and the paints. It's about what the painter does with them.

[knagl]

For what it's worth, this article really applies to slot machines -- not Video Poker (save for the fact that a 9/6 game one day might be something else another day, but it would be "advertised" as such, too).
 
A few Nevada casinos are just starting to experiment with "downloadable" games.  Most machines still require the lengthy process of a physical change-out of computer chips to change the paytable of the machine (or change the payout percentage of the slot machine).