V functions.php naslednja koda. Pomembno je, da se checkout osveži po spremembi parametrov (zaradi izračuna):

//1
add_action('woocommerce_cart_calculate_fees', 'add_cod_fee_based_on_shipping', 20, 1);
function add_cod_fee_based_on_shipping($cart) {
    if (is_admin() && !defined('DOING_AJAX')) {
        return;
    }

    // Check if COD is selected
    if (WC()->session->get('chosen_payment_method') === 'cod') {
        // Get the chosen shipping method
        $chosen_shipping_methods = WC()->session->get('chosen_shipping_methods');
        
        if ($chosen_shipping_methods) {
            $chosen_shipping = explode(':', $chosen_shipping_methods[0])[0]; // Extract method (ignoring instance id)
            
            // Apply only for shipping, not local pickup
            if ($chosen_shipping !== 'local_pickup') {
                // Add a €2 fee for COD
                WC()->cart->add_fee(__('Plačilo po povzetju', 'your-text-domain'), 2);
            }
        }
    }
}
//2
add_action('woocommerce_cart_calculate_fees', 'add_leanpay_fee', 20, 1);
function add_leanpay_fee($cart) {
    if (is_admin() && !defined('DOING_AJAX')) {
        return;
    }

    // Check if Leanpay is selected
    if (WC()->session->get('chosen_payment_method') === 'wc_leanpay_module') {
        // Add a €5 fee for Leanpay
        WC()->cart->add_fee(__('Stroški obdelave Leanpay', 'your-text-domain'), 5);
    }
}
//3
add_action('wp_enqueue_scripts', 'refresh_checkout_on_change');
function refresh_checkout_on_change() {
    if (is_checkout()) {
        ?>
        <script type="text/javascript">
            jQuery(function($){
                // Trigger update when payment method is changed
                $('form.woocommerce-checkout').on('change', 'input[name="payment_method"]', function() {
                    $('body').trigger('update_checkout');
                });

                // Trigger update when shipping method is changed
                $('form.woocommerce-checkout').on('change', 'input.shipping_method', function() {
                    $('body').trigger('update_checkout');
                });
            });
        </script>
        <?php
    }
}

//4
add_filter('woocommerce_package_rates', 'hide_shipping_when_free_is_available', 100, 2);
function hide_shipping_when_free_is_available($rates, $package) {
    $free = array();
    $local_pickup = array();

    foreach ($rates as $rate_id => $rate) {
        // Check if it's free shipping
        if ('free_shipping' === $rate->method_id) {
            $free[$rate_id] = $rate;
        }
        
        // Always keep local pickup
        if ('local_pickup' === $rate->method_id) {
            $local_pickup[$rate_id] = $rate;
        }
    }

    // If free shipping is available, return only free shipping and local pickup
    return !empty($free) ? array_merge($free, $local_pickup) : $rates;
}
//5
add_action('wp_footer', 'refresh_checkout_on_payment_method_change');
function refresh_checkout_on_payment_method_change() {
    if (is_checkout()) {
        ?>
        <script type="text/javascript">
            jQuery(function($) {
                // Trigger the WooCommerce checkout update when payment method is changed
                $('form.woocommerce-checkout').on('change', 'input[name="payment_method"]', function() {
                    $('body').trigger('update_checkout');
                });
            });
        </script>
        <?php
    }
}