Here is a result. I created a mobius with 60 degree angles which left it "unconnected" at the ends. Then i could unwrap the 2 edges to create the "unwrapped mobius base object.

Now doing curve to curve flow on that surface with varying lengths of base curve, you can see what is happening to your metal.

This result i made used the base curve of the shorted surface which results in "tip to tip" connection. If you shorten the base curve (Shown by text) you will see the surface created with overlap and also not really "meet at the edges". This is the stretching

If I adjust the mobius to "connect before the unwrap" you will see it is no longer a tangent surface with equal "width" throughout, but a variable.... I would have to adjust my unwrap to match this.

But either way, I can divide the text at the 180 and create surfaces that dont twist to match the distortion and then flow text undistorted...

But my previous post was "why"? Arent you just looking for bend points for the machine to bend metal? Why are we creating the surface?