Found the solution by simply trying it out.
If you choose the option "import settings from disk" you go back to an earlier stage, and destroy the current photo.
If you choose "overwrite settings" you overwrite older data with your latest edit adjustments.
So, to preserver the current image, "overwrite settings" is correct.
It's a bit a misnomer. "update" would be more precise, because update means to replace older settings with new ones.