Hi Andrei - every closed curve still has a start and end point to it. When you do a loft between closed curves, if it just connected the curves together by this natural start points it would often product a twisted result unless those points were all aligned with one another.

So in order to reduce twisting MoI goes through a process of "seam alignment", where it relocates the seam point of a closed curve by cutting the curve at the new seam point and gluing together the other pieces. This seam alignment step changes the structure of the curve so the "seam aligned" curves are not exactly the same curves as your starting ones. That's the reason why they don't have the same structure when they are lofted.

- Michael