menu_order not working with slugs that start with admin.php

I am filtering the menu_order hook (codex link) to change the order of my links in the admin menu. Currently the ordering will not work on slugs that begin with admin.php, so a settings page with the slug “admin.php?page=custom_settings_page” will just go to the bottom of the list. Anyone know of a workaround for this?

//change admin menu order
add_filter('custom_menu_order', 'my_custom_menu_order'); // Activate custom_menu_order
add_filter('menu_order', 'my_custom_menu_order');

function my_custom_menu_order($menu_ord){

if(!$menu_ord) return true;
return array(
    'index.php', //dashboard
    'separator1', //first separator
    'edit.php', //posts
    'edit.php?post_type=custom_post_type1', //custom post type 1
    'edit.php?post_type=custom_post_type2', //custom post type 2
    'edit.php?post_type=custom_post_type3', //custom post type 3
    'upload.php', //media
    'separator2', //second separator
    'admin.php?page=gf_edit_forms', //THIS GOES TO THE BOTTOM
    'edit.php?post_type=page', //pages
    'edit-comments.php', //comments
    'separator-last', //last separator
    'themes.php', //appearance
    'admin.php?page=custom_settings_page', //THIS GOES TO THE BOTTOM
    'plugins.php', //plugins
    'users.php', //users
    'tools.php', //tools
    'options-general.php' //WordPress options
);

}