Curve on Unrolled Surface, UV coordinates not matching

Hi!

I am drawing a curve on an unrolled surface and rebuild it on the corresponding 3D surface with the UV coordinates retrieved by "curve division" and "closest point". When now unrolling the newly created curve there is a mismatch of about 40 mm in the horizontal position to what was originally drawn. This mismatch is also measured on the 3D surface, so it's not an unroll issue.

For testing reasons I also recreated the curve with UV coordinates on the 2D surface, where the position turns out correct. 

Is there anything I have missed? It seems like a very straight forward process, but I'm kind of stuck at this point. I would be glad for any help!

Thanks,

Julian

Screen captures attached: