Partially Solved: Help with unexpected gradient color results, appears to keep using X instead of Z

Trying to get the surface to be colored based on z-height. I used a few different techniques from centroids to fully exploding, but the colors keep sweeping in the X direction instead of the Z.

Can’t figure out why or what I’m doing wrong here.

Gradient Color (16.6 KB)

How about using mesh instead?

Gradient Color (22.5 KB)


Is converting surfaces like this to a mesh the generally preferred way to do this?