How to Add a Sub Menu Page to a Custom Post Type?
add_options_page() automatically adds it underneath settings, however add_submenu_page() gives you control as to where you want it to show up. Try something like this: add_submenu_page( ‘edit.php?post_type=portfolios’, __( ‘Test Settings’, ‘menu-test’ ), __( ‘Test Settings’, ‘menu-test’ ), ‘manage_options’, ‘testsettings’, ‘mt_settings_page’ );