Yeah while it is in the process of dicing MoI is actually dicing up NURBS surfaces, they only become polygons in the last stages. Also on top of that trim curves are diced up into small pieces as well to make trim boundaries. That whole process takes up a bunch of additional overhead to sort of "set the stage" for stuff before the polygons are even created. It's usually not the polygon data itself that really takes the most space, more all that in between stage calculation stuff.

When you're in the polygon app there is none of that other stuff existing at that point, only the final result, that's why the capacity is different.

- Michael