No matter how the points are divided, they can’t change that number. However, what they can do is change seasons, change nights, etc. it as mentioned, they have to reduce elsewhere. A few years after I bought in 2009, the weekend points were lowered, and weeknights were raised to balance out demand. So, people who bought thinking their 5 night stay would cost X, found it went up a little. But people who were having to go and include the weekends so the cost of their trip go down.
When buying, I would be sure to consider that cushion. The easiest way I think about it is using Magic Season as a guide and buy based on that, even thoughI might travel the other times. If you know you will always go during the current Magic Season, then I’d be sure to consider having a cushion of a few extra points.