So, I found out something that I think is a bit odd.
Apparently restscale will override restlength of a vellum source for some reason.
I always thought that @restlength = restlength*restscale;
But after manipulating the restlength of a vellum strut object in SOP if I use restscale =1 in DOP the result should be the same as if I don't use anything, but what I get is equivalent to replace restlength to 1.

Is there some technical issue I am missing here?