I'm sure some of our users could help you out but for such an in-depth question, a packaged workbook with sample data would be extremely useful. if you have sensitive data, I would check out Anonymize your Tableau Package Data for Sharing.
Even you don't have for NOV, DEC months, we can create YTD Calculations like Below,
if year([Order_Date])= year(today()) and
then ([Sales]) end