The documentation for filefield_sources_plupload_submit() seems to indicate that it's not needed after #1329056: "Add a new file" form disappear after selecting existing file is fixed.

/**
 * We need our own submit handler until the following issue gets resolved:
 * http://drupal.org/node/1329056
 *
 */

This issue has been fixed since July now, with new stable releases that provide the needed fixes. Can this function then safely be removed from the project?

p.s. Great work on this project! Shockingly short (though not simple) implementation. The multiple file handling is impressive. :)