Comparing all ceilings from New Arch Model to old Arch Model

hello, I am trying to write a scrip that will hopefully show me visually what the difference is in an old arch models ceilings to its new ones. With that being said. I have run into some difficulties with error messages right off the bat. Below you see that I am getting an error message where the element.geometry node is picking up dozens of random items that dont even exist in the list feeding into it.

  1. How is this possible?
  2. What does it mean?
    Then, I am getting an error message when I simply try to extract the Level parameter from my ceilings why is that? Is there another way to get its level?

Have you took a look at this from @Mostafa_El_Ayoubi?