List Feed to BBStyle CellRange for BumbleBee Formatting

Apologies if this is an idiotic question from someone pushing beyond their base knowledge.

My understanding was that a list of strings (based on the primer instructions) could be fed to the CellRange for formatting in excel via Bumblebee.

I’ve used a python script to grab the header rows from the Revit schedule and in coordination with the start row defined pulled these out as rows to be highlighted bold in excel.
I know the style part going in is fine as if I replace the list with a single string or code block to a single range it is behaving. I did try nesting each row back a level in the list as well, but did not have any joy.

Thoughts or pointers welcome as looking to try and use this technique for quite a bit including revision tracking and highlighting.