Is this new or does this penalty only apply to XY? I flew LAX-RAR-AKL and returned AKL-Nadi-LAX with NZ in late 2001/early 2002 and was charged the usual 90,000 for a seat in C. No stopovers, just a few hours on the ground there and back. Not my choice either, just the only option for getting a seat.
Good luck getting the change.