No. I meant that using search/replace *is* a good idea. Apologies for tortured grammar.
Calibre sets the author_sort field for new authors by following the tweak. If the tweak is set to what you want (and I am no longer sure what that is), then it will happen automatically.
Fetching metadata is another issue. Sometimes that metadata changes the values of author and/or author_sort for the books in question. If you don't like the results, you must fix them manually.
You could actually try it and see what happens.