I'm trying to change title and meta description for pages used for products. The goal is to have the same effect as here: <script>document.title = "<?php echo $new_title; ?>";</script>

The page with lists of products is a template where are includes in some conditions.

template_listing.php:

if (!empty($offer['listingId']))
    include('include_offer.php');

I'm struggling with how to change title/description in include_offer.php. My findings so far:

function wp1_filter_wp_title($title) {

if (is_page_template('include_offer.php')) {
    return 'some title';
}
return $title;
}
add_filter('pre_get_document_title', 'wp1_filter_wp_title');

But it doesn't work. It's working only if if (is_page_template('template_listing.php')). Is there any function like 'is_page_template' which also works for included pages?

Edit:

function show_template() {
global $template;
echo basename($template);
}

basename on that single product page return 'template_listing.php'

I also figured out there is function get_included_files but I'm not sure how to use that in my case.