I seen this script too but as you say, the vanilla "ChangeAtZ" does not have Z-hop support either but I guess it would be quite easy to add that to the script.
The dots is an extra surface, at first I found it convenient to keep it since it worked as a separator and made adjusting the "tower" positions of the modell easier when I was modelling it and test printed to find the exact correct position. But Now when that is done I found out this surface had another nice little feature, it made a foundation for the tower legs so they attach to the core of the bottom plate and not just on the surface. So that is why I did not remove it.