Within any one game the distribution remains the same. But for each time the game is launched we might want it to select a distribution randomly from a set of 5 or 10 or 20 distributions.
Aim is to get the idea of probability. If the NAG distribution is skewed towards low numbers you are more likely to do well. If it is skewed towards high numbers you are less likely to do well. But if your only aim is to beat a competitor then that doesn’t matter.