If there is a hypothetical VP machine where the paytable changes based on time, I have never seen or heard of it.
I am sure that in Nevada, there is no current law to allow the slot machine theoretical to be changed without a whole bunch of paperwork and hoops to jump through. There is no way that the slot product is in play.
I will do some checking though.
Even though it's legal in many jurisdictions, is it commonly used for slots in casinos? It's definitely not for video poker.
Is it commonly used for slots? I personally don't know of any casinos doing it.
Should also state if there were a paytable change on these machines, we would still count it as a new machine and would again require a tech changing the paytable at the machine with Regulatory standing there watching it all and then sealing the board. We really are not required to seal all the stuff we do at my store, but I think it is a good practice.
Most of the machines that are capable of this are server based. Changes are usually made from the SBX console.