Order total price calculation

[lupus]

Hello.
As I can see when the total product price is calculated (Order.php, line 575):

$total += floatval($row['product_price']) * $qty * (1 + $row['tax_rate'] / 100);

there is multiplication of price without tax, quantity and tax rate.

Honestly, I prefer to calculate product total like that:

$unit_with_tax = round(floatval($row['product_price']) * (1 + $row['tax_rate'] / 100), 2);
$total += $unit_with_tax * $qty;

so first the product unit price with tax is calculated, then the value is multiplied by quantity.
Any comments are welcomed.