Hello @RoyBatty279
And just for the records as @aworker already provided the solution. As I was pointing in my previous post, your only data complexity resides in the arrangement of your data; it is only a transformation issue, then displaying it in two columns by un-nesting the timeseries $Days$ simplifies the difference calculation:
Once done, it is easy to rearrange at any desired format:
20220523_nested_hierarchy_column_names.knwf (95.6 KB)
BR