Grasshopper gene pool

Hi i’d like to enlarge some parts
so i used scale and gene pool

It works but dont know why it appeared as 2 group of curves

and other question, i want to increase or decrease a specific section on the xy plane based on the z-axis as a reference

and then is it right to use the gene pool to make the changes in the whole objects naturally?

gene pool 0517.gh (33.6 KB)