I took a dragon image and did a few images to show the difference as to where you put the xy.
First, put the xy at approximately the center of your image.
BA.Fan illusion.Dragon.36 slices. xy at center of image.png (373.68 KiB) Viewed 493 times
The next one is with the xy at the bottom of the image. If you do not make a final correction, the top slice will show your initial image. Sometimes you may not want that.
BA.Fan illusion.Dragon.36 slices. xy at botttom of image.png (209.76 KiB) Viewed 493 times
To correct, duplicate your image. Rotate the underneath layer 180 degrees. Make sure the top layer has an alpha channel. Erase over the top layer to show the layer underneath so that your image is the same all around. Then merge the top layer to the second layer.
BA.Fan illusion.Dragon.36 slices. xy at botttom of image.Fixed.png (211.24 KiB) Viewed 493 times
The last image is using the bounding box choice. This is using centered, cropped (all done by the script)
I have already installed the new version, now I will explore the script.
Thank you for the explanation.
The manipulations are the fruit of your work to create, Scripts, Plugins, and Tutorials, without it never would never do these works.