Data with a bit higher variance is a great application. I’d love to get into the math, but it is a wee bit complex and confusing! I’d love to get into it when I have the time. The model can be a bit finicky through Sklearn i’ve found. It’s a hard one to program, Fabian Pedrogosa programmed it into Sklearn, he has a little post about it here:

Isotonic Regression

But to get the mathematics behind it would require a bit more formula searching.