Is it on LOT (as LOT is the only airline I know with 3 x 32kg C-class allowance)?
If it is LOT the 4th piece maximum weight is 32kg.
Wow, double checked the TK website and it looks like they have decreased regular Business allowance to 2 x 32kgs on that route.
Since I haven't flown paid TK J on a piece-concept route for at least 10 years, I never realized the decrease which might have even been taken in place a few years ago.