Slice problem with "end offset" and visalizing entire photo.

Regarding Slices. I have a Mac Book Pro using Big Sur. The "end offset" setting for which it allows the user to see the completed photo doesn't work for individual slices of a puzzle piece, for example. It works for all "overlap" dropdowns except for simultaneous when you use the slice as a whole, and not individual puzzle pieces. Am I doing anything wrong, or is it my computer? My workaround is to set a transition to "0" and copy the previous slide while I set the keyframes to reflect the photo as a whole, and not sliced up. Can anyone help me with the "end offset" problem. Thank you.