Thank you for the great script.
I have tried to use this script, but I want a slightly different setup. Do you know how you can change this script so the pivot point is set to the bottom left back?
import bpy
from bpy import context as C
for z, co in [(o.bound_box[0][2], v.co) for o in C.selected_objects for v in o.data.vertices]:
co.z -= z