3d movement using the 2d paths

I have been using the basic AIPath script with some mods and I would like the units to be able to move in 3d space.
I understand there is limitation with that the paths are in 2d. Maybe the basic AIPath script does support movement in “3d” but I got some of the settings, wrong as it can’t find a path to the point. In that case I assume that I missed a variable where I can set the max height a point can be above the graph to be considered reachable.

Any suggestions?