BlendSurface blends in the wrong direction

Hi guys,

I need your help with hopefully a simple problem. I try to create a blended edge between two surfaces, but the BlendSurface function doesn’t work as expected. While one end of the blend is fine, the other blend is turned inward and no matter how much I try of adjust the handles it just won’t have it.
View1 shows the blend at the end where it’s correct, View2 shows the end where it’s wrong. I just can’t work out why or what I’ve done wrong. I also tried to blend just the end in View2 on its own and it keeps doing it.
Any ideas?

Many thanks, and as I said, I hope it’s something simple…

I think I finally worked it out - you need to click the handles with ALT pressed. I still don’t know why it defaults inward at that end.
Somehow the blend now goes inward halfway along though…

Can you post the 3dm? It might be pick location at a guess.