Circle fit not acting as anticipated

Hi all,

I have a script that helps to name elements based on floor level (Z coordinate), number sequence (number of elements on the Z coordinate) and layer name.

this works absolutely fine for basic geometry, no issues, each Z coordinate can be numbered (list length) and that used to give its floor level or height.

I have been using circle fit to determine the horizontal numbering (follow this path around clockwise, number each piece separately.

again, this works fine on basic geometry (attachment 1), however, when I add new geometry (windows, Attachment 2) the circle fit fails to recognize it. there are only 2 elements within these new circle fits. what is going on here? does circle fit require more than two elements to determine a suitable circle?

if that is the case, what other options do I have for consecutive numbering around a 'circular' path?

Many thanks!

Alec