Loop through named range backwards and populate based on criteria from adjacent cells

Hi again, I am still working through this spreadsheet problem where I need to populate the three columns I need for input to another function.

I have populated the "ON" and "BC" columns and now I need to loop through the "Range_ITC" named range backwards to populate it based on the criteria that I have entered on the spreadsheet.

The problem for me is referencing offset cells both to the left and below the target cell while stepping backwards to the top of the range.

As usual, any guidance would be greatly appreciated.

Regards,

Craig