According to the link below
- upgrades with *A are the same price as J awards
- upgrades for most carriers can be only done for high end Y booking classes
- so it seems paying with miles for upgrades does not really make sense; book your award in J directly instead for the same mileage (maybe taxes make the difference)

https://www.turkishairlines.com/en-i...award-tickets/ (Star Alliance upgrade awards)