Boundary Surfaces Loses 1 value from list

I have a script for a twisting tower.

I have used this last part of the script before with no problems. Suddenly boundary surfaces is causing an issue. It’s losing 1 value from the list. 71 values go in, 70 come out. And thus I have one floor of my tower that has no floor plate for some reason. I’ve tried grafting, etc. nothing is working to resolve this.

I’m attaching a photo.

Please help!! :slight_smile:

Thanks !