Grading Cut/Fill calculations only work when one Toposurface is present in the model

[jagostinho74]

Founding that when using the Graded Region tool the Cut/Fill calculations are only performed if a single toposurface element is present in the model as per the video below.

Is this happening to you as well?

Model file with toposurfaces also available.

[alan_eu]

Not only having toposurfaces, but also having them duplicated with graded region made with different phases...