The tag browser always uses author_sort for sorting authors. The tweak determines what is displayed: author or author_sort. Note that the main gui also always uses author_sort: if the author_sort value for Emily Bronte is "Bronte, Emily", then she will show up under 'B', not 'E', in both the main gui and the tag browser.
If you want to sort authors in the way they are written, then you must change the value of author_sort. The change will affect the tag browser and the main gui. See
http://manual.calibre-ebook.com/faq.html#id38 for some information on how calibre sorts authors.