Surface from U-Points | U Count

I’m having some trouble with getting a curve to follow a surface.
I suspect the problem is my knowledge of how Surface from Points work, in particular U-Count.
I’ve watched a video on what U-count is, but still not clear in my head how this works.
In the screen recording below, I can enter a U-count of 3 & 9, however, I don’t seem to be able to enter any other value. I think this is to do with how the number of points could be calculated by multiplying rows and columns (2x3 = 6, 3x3 = 9), but I’m a bit stuck.

I’ve also used the BREP export from the Archicad Mesh node.
I think this method is going to be the way forward, as it resembles how the native tool looks in AC.
I’m some troubles thou with separating the top faces, form the bottom and sides.
Not sure what commands I would enter to separate these.
Also GH appears to freeze and have some odd behavior when connecting.

Driveway (52.9 KB)