Surface Layout Problem

Hello All,

I'm working on a definition to create terrain, scale, contour and lay it out for laser cutting. I have a few issues in my file, but the most pressing (and confusing) is the issue illustrated in the above screenshot. I have sliced my Brep into 7 contours and labeled it with its corresponding List number. When I move them that the number doesn't remain the same as before, i.e. they are being sorted in a seemingly random order. Any and all help is appreciated.

Cheers.