IMHO there is a misconception in how the prefix options are coded.

If you add a "Filename prefix", let's say "AA - " and also check the "Prefix filename with page title" the result should be:
"AA - 'Page Title'" instead of "'Page Title' AA - " that is how it currently works.

Besides, it is not possible to left the "File name prefix" blank. I cheat the extension adding an space.