Hi Mike
By reading your observations, I have checked again
the file I sent, actually something is wrong,
the profiles, which are dorsal oriented that determine the volume
are badly oriented and thus produce a final screwing,
I've reviewed the file that you find at this link:
http://www.mediafire.com/file/9u89bmm8b6lfgyj/Rev-Solidify_Moebius_Strip.rar
I also added some pictures that will make you better
the question...
In the end however, as you see the result is a solid one
best
al