This script can be used to compensate interpolation drifting by adding a forward (z) offset.
By default zoffset = 10 is quite big. It meant to show whether the new animation was imported correctly.
Once you are sure your setup is working correctly you can use a better offset, more like 2 to 5.

Usage:

- Select only the pelvis of a character.
- Press [alt] + 4 to open the script editor.
- Set the desired Z offset, export folder and export file name.
- Press F5 to run the script.