protected function _getMultiplier()
    {
        $dAmount = 0;

        if ($this->getCalculationRule() == self::CALCULATION_RULE_ONCE_PER_CART) {
            $dAmount = 1;
        } elseif ($this->getCalculationRule() == self::CALCULATION_RULE_FOR_EACH_DIFFERENT_PRODUCT) {
            $dAmount = $this->_iProdCnt;
        } elseif ($this->getCalculationRule() == self::CALCULATION_RULE_FOR_EACH_PRODUCT) {
            $dAmount = $this->_iItemCnt;
        }

        return $dAmount;
    }