protected function _calcPaymentCost()
    {
        // resetting values
        $oPaymentPrice = oxNew(\OxidEsales\Eshop\Core\Price::class);

        // payment
        if (($this->_sPaymentId = $this->getPaymentId())) {
            $oPayment = oxNew(\OxidEsales\Eshop\Application\Model\Payment::class);
            $oPayment->load($this->_sPaymentId);

            $oPayment->calculate($this);
            $oPaymentPrice = $oPayment->getPrice();
        }

        return $oPaymentPrice;
    }