Async JavaScript Plugin – Scripts to Defer not working for me

could be due to your theme (or a plugin) is adding those 3 JS-files late skytower1 (as if after AsyncJS did its job). this is (somewhat) confirmed by the fact that when loading your page without Autoptimize being active (by adding ?ao_noptimize=1 to the URL), the jquery.min.js file isn’t even loaded.

also; you might want to take a look at why you have PHP-code showing up at the top of your page source:

/**
 * Defer parsing of javascript.
 */
if (!(is_admin() )) {
    function defer_parsing_of_js ( $url ) {
        if ( FALSE === strpos( $url, '.js' ) ) return $url;
        if ( strpos( $url, 'jquery.js' ) ) return $url;
        // return "$url' defer ";
        return "$url' defer onload='";
    }
    add_filter( 'clean_url', 'defer_parsing_of_js', 11, 1 );
}

Frank,

This was added into the functions.php page by myself.
It does not work.

I noticed that these 3 js are keeping loaded from header.php
I then moved them to body section, and added defer tag manually
It works now.

Now I have a 97% score.

Do you have any suggestions about optimizing Fully Load Time?

I noticed that these 3 js are keeping loaded from header.php

that explains why AsyncJS didn’t pick those up; the scripts are hardcoded in the .php, but the proper way of adding JS is done by registering and enqueueing JS (and CSS). AsyncJS hooks into that queueing mechanism to add the flags.

Do you have any suggestions about optimizing Fully Load Time?

Don’t worry too much about fully loaded, focus on “start render” which measures how long it takes for the user to see *something* and “onload” (aka “document loaded”)
which measures how long it takes for the main resources to load (and finish rendering).