> Actually, I have found a way, but it is cheating, and not suitable for a
> real-life project.

Indeed. starting from the wrong end would just swap one problem for
another ;)

I added an "Important note" to the end of this:
https://therion.speleo.sk/wiki/breakingextend

Summary:
As it currently stands, it does not seem to be possible to break an
extended elevation at the "end" of a loop, along the shorter side of the
loop (or whichever path Therion chooses as its primary path around the
loop).
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