algorithmic modeling for Rhino
I just had this same problem. I tried flip, evaluate, you name it and even when I would get the vectors displayed properly, the surfaces would still offset in different directions. What worked for me was to input the surfaces into an explode brep component and then run the edges into a new planar surface component. This is strange because if I made a brep first and used it as input into the explode component, it would output faces with differing normals. To me I thought once a surface was joined the normals of the brep all became oriented but this doesn't seem to be the case for the faces and yet it is for the curves???