Issue #3268581 by jsacksick, gge: Wrong price and order subtotal calculation...

        return;

      }

      // Display-inclusive promotions must first be applied to the unit price.

      $amount = $adjusted_unit_price->multiply($percentage);

      $unit_price = $order_item->getUnitPrice();

      $amount = $unit_price->multiply($percentage);

      $amount = $this->rounder->round($amount);

      $new_unit_price = $order_item->getUnitPrice()->subtract($amount);

      // Don't reduce the unit price past 0.

      if ($amount->greaterThan($adjusted_unit_price)) {

        $amount = $adjusted_unit_price;

      }

      $new_unit_price = $unit_price->subtract($amount);

      $order_item->setUnitPrice($new_unit_price);

      $adjustment_amount = $amount->multiply($order_item->getQuantity());

    }

    else {

      $adjustment_amount = $order_item->getTotalPrice()->multiply($percentage);

      $adjusted_total_price = $order_item->getAdjustedTotalPrice(['promotion']);

      $adjustment_amount = $adjusted_total_price->multiply($percentage);

      // Don't reduce the order item total price past zero.

      if ($adjustment_amount->greaterThan($adjusted_total_price)) {

        $adjustment_amount = $adjusted_total_price;

      }

    }

    $adjustment_amount = $this->rounder->round($adjustment_amount);