根据类别向每个产品的WooCommerce添加费用并添加到销售税

Question

我见过几个与基于类别向WooCommerce项目添加服务费有关的帖子。在我的情况下门票。我已经成功完成了几个代码。但是，在所有情况下，销售税都未应用于新的子总计。我试图让这种情况发生。因此，根据下面的代码，我不会因征收税款而征收上缴费用。 以下是我目前正在使用的代码：

/* Service fee for tickets */

function df_add_ticket_surcharge( $cart_object ) {

global $woocommerce;
$specialfeecat = 23; // category id for the special fee
$spfee = 0.00; // initialize special fee
$spfeeperprod = 0.214; //special fee per product

foreach ( $cart_object->cart_contents as $key => $value ) {

    $proid = $value['product_id']; //get the product id from cart
    $quantiy = $value['quantity']; //get quantity from cart
    $itmprice = $value['data']->price; //get product price

    $terms = get_the_terms( $proid, 'product_cat' ); //get taxonamy of the prducts
    if ( $terms && ! is_wp_error( $terms ) ) :
        foreach ( $terms as $term ) {
            $catid = $term->term_id;
            if($specialfeecat == $catid ) {
                $spfee = $spfee + $itmprice * $quantiy * $spfeeperprod;
            }
        }
    endif;  
}

if($spfee > 0 ) {

    $woocommerce->cart->add_fee( 'Service Fee', $spfee, true, $taxable = true, $tax_class = 'standard' );
}