This looks great. Thank you for sharing. You might consider calling the line something other than Reference Line since that is a different thing in Tableau that the system automatically creates. This is a great viz though and thank you for sharing. You might also want to document this in the Workbook & Calculation Library. Be sure to use the template provided if you do that.
Apologies for replying after so long !!
Thank you for the suggestion. I will surly look in that. Also I will explore the option to document the same in the Tableau Workbook Library.