Hi Mike, thanks for sending the sausage file.

In this case it's the segmented nature of those concave sections that's causing the problem, it looks like there is probably some uneven parameterization in some segments, which is not good for the seam matcher.

It's probably something that I can fix up, but an easy solution for the moment is to select all those sweep profiles and run Rebuild on them, the rebuilt curves have better parameterization and the rebuilt ones should all sweep fine.

- Michael