如何显示保存在woocommerce单个产品页面上的折扣？

Question

以下代码将显示简单产品和可变产品在价格下节省的折扣。但是，当我按照此处"Replace the Variable Price range by the chosen variation price in WooCommerce 3"的建议安装代码段时，为可变产品保存的折扣消失了。

// For simple products
add_action( 'woocommerce_single_product_summary', 'simple_product_saving_amount', 11 );
function simple_product_saving_amount() {
    global $product;

    if( $product->is_type('simple') && $product->is_on_sale() ) {
        $regular_price = (float) wc_get_price_to_display( $product, array('price' => $product->get_regular_price() ) );
        $active_price  = (float) wc_get_price_to_display( $product, array('price' => $product->get_sale_price() ) );

        $saved_amount  = $regular_price - $active_price;
        $percentage    = round( $saved_amount / $regular_price * 100 );

        echo '<p id="saving_total_price">'. __("You Save") .': ' . wc_price($saved_amount) . ' ('.$percentage.'%)</p>';
    }
}

// For product variations (on variable products)
add_filter( 'woocommerce_available_variation', 'variable_product_saving_amount', 10, 3 );
function variable_product_saving_amount( $data, $product, $variation ) {

    if( $variation->is_on_sale() ) {
        $saved_amount  = $data['display_regular_price'] - $data['display_price'];
        $percentage    = round( $saved_amount / $data['display_regular_price'] * 100 );

        $data['price_html'] .= '<p id="saving_total_price">'. __("You Save") .': ' . wc_price($saved_amount) . ' ('.$percentage.'%)</p>';

    }
    return $data;
}