Reactor point and array

Hi guys, I am working on "reactor points" and "arrays".
As you can see, there is a grid of points and a surface generated from the distance between all the grid points and the "reactor point" in the center of the squared surface. 

I would duplicate that surface but with different height. 

I tried to create a rectangular array as you can see but I don't know how to change the others... is that the right way?

Please suggest me,

thanks.