Os custos de envio variam dependendo da quantidade de itens

add_filter('woocommerce_package_rates', 'adjust_shipping_based_on_item_count', 10, 2);
function adjust_shipping_based_on_item_count($rates, $package) {
    $item_count = WC()->cart->get_cart_contents_count();

    if ($item_count > 5) {
        foreach ($rates as $rate_id => $rate) {
            $rates[$rate_id]->cost += 2.00; // Zusätzliche Versandkosten ab 6 Artikeln
        }
    }

    return $rates;
}