Add tax after specific price reduction

[cm_w89]

Hi, I'm using PrestaShop 1.6.1.0. I have applied a specific price discount on a product. But when it comes to adding tax. It's being added on the base price not on discounted price.
What should I do?

Code in my Classes/Product.php:
 

$specific_price_reduction = 0;

if (($only_reduc || $use_reduc) && $specific_price)

{

if ($specific_price['reduction_type'] == 'amount')

{

$reduction_amount = $specific_price['reduction'];

 

if (!$specific_price['id_currency'])

$reduction_amount = Tools::convertPrice($reduction_amount, $id_currency);

 

$specific_price_reduction = $reduction_amount;

 

// Adjust taxes if required

 

if (!$use_tax && $specific_price['reduction_tax'])

$specific_price_reduction = $product_tax_calculator->removeTaxes($specific_price_reduction);

if ($use_tax && !$specific_price['reduction_tax'])

$specific_price_reduction = $product_tax_calculator->addTaxes($specific_price_reduction);

}

else

$specific_price_reduction = $price * $specific_price['reduction'];

}