I think I realized something.
I am graduating prism levels too quickly. I will make very good apparent progress with the prisms, and that will cause me to use less. I think I need to stop doing that, and keep using the prism even when I think I don't.
Because what seems to be happening is that I make good progress, and then I use far less prism (or none), and then I don't want to say that I go backwards exactly, but it becomes apparent later that I'm not ready for it. The prisms definitely do free up energy to work on other tasks, like fusion. It's far easier and less energy expensive to get the accommodation in sync, while fusing, if I'm using the prisms--even if I don't think I need it. I've made this realization in the past, but I needed re-realize it.