Error inter version? Product.php and Quantity_discount

[Laproteina]

Hello , sorry poor english
I download svn to my computer.
I saw in version 1373 of Product.php(made by mBiart) that includes this code to fix discount quantity when ordering different combinations

$totalQuantity = intval(Db::getInstance()->getValue('
           SELECT SUM(`quantity`)
           FROM `'._DB_PREFIX_.'cart_product`
           WHERE `id_product` = '.intval($id_product).' AND `id_cart` = '.intval($cookie->id_cart))
       ) + intval($quantity);
       if ($totalQuantity > 1 AND ($qtyD = QuantityDiscount::getDiscountFromQuantity($id_product, $totalQuantity)))
           $price -= QuantityDiscount::getValue($price, $qtyD->id_discount_type, $qtyD->value);

Introduces the var $totalQuantity

But in actual version on this file anybody's do something with this var
I saw version 1589(made by rGaillard) changes this code

            if ($totalQuantity > 1 AND ($qtyD = QuantityDiscount::getDiscountFromQuantity($id_product, $totalQuantity)))
               $price -= QuantityDiscount::getValue($price, $qtyD->id_discount_type, $qtyD->value);

by

        if ($quantity > 1 AND ($qtyD = QuantityDiscount::getDiscountFromQuantity($id_product, $quantity)))
       {
           $discount_qty_price =  QuantityDiscount::getValue($price, $qtyD->id_discount_type, $qtyD->value);
           if (!$usetax)
               $discount_qty_price /= (1 + ($tax / 100));
           $price -= $discount_qty_price;
       }

It's a error? the var totalQuantity not used at this moment, the different combinations dont work or not?
This var not used in 1.3 RC3 released