diff --git a/classes/order/OrderDetail.php b/classes/order/OrderDetail.php
index 2232006a1..a1184ea2b 100644
--- a/classes/order/OrderDetail.php
+++ b/classes/order/OrderDetail.php
@@ -292,7 +292,7 @@ class OrderDetailCore extends ObjectModel
 	 * @since 1.5.0.1
 	 * @return boolean
 	 */
-	public function saveTaxCalculator()
+	public function saveTaxCalculator(Order $order)
 	{
 		// Nothing to save
 		if ($this->tax_calculator == null)
@@ -304,8 +304,12 @@ class OrderDetailCore extends ObjectModel
 		if (count($this->tax_calculator->taxes) == 0)
 			return true;
 
+		$ratio = $this->unit_price_tax_excl / $order->total_products;
+		$order_reduction_amount = $order->total_discounts_tax_excl * $ratio;
+		$discounted_price_tax_excl = $this->unit_price_tax_excl - $order_reduction_amount;
+
 		$values = '';
-		foreach ($this->tax_calculator->getTaxesAmount($this->unit_price_tax_excl) as $id_tax => $amount)
+		foreach ($this->tax_calculator->getTaxesAmount($discounted_price_tax_excl) as $id_tax => $amount)
 		{
 			$unit_amount = (float)Tools::ps_round($amount, 2);
 			$total_amount = $unit_amount * $this->product_quantity;
@@ -531,7 +535,7 @@ class OrderDetailCore extends ObjectModel
 		$this->save();
 
 		if ($use_taxes)
-			$this->saveTaxCalculator();
+			$this->saveTaxCalculator($order);
 		unset($this->tax_calculator);
 	}
 
diff --git a/classes/order/OrderInvoice.php b/classes/order/OrderInvoice.php
index 82f681546..bf1d601c7 100644
--- a/classes/order/OrderInvoice.php
+++ b/classes/order/OrderInvoice.php
@@ -250,7 +250,7 @@ class OrderInvoiceCore extends ObjectModel
 		if ($this->useOneAfterAnotherTaxComputationMethod())
 		{
 			// sum by taxes
-			$taxes_by_tax = Db::getInstance()->executeS('
+			$taxes_infos = Db::getInstance()->executeS('
 			SELECT odt.`id_order_detail`, t.`name`, t.`rate`, SUM(`total_amount`) AS `total_amount`
 			FROM `'._DB_PREFIX_.'order_detail_tax` odt
 			LEFT JOIN `'._DB_PREFIX_.'tax` t ON (t.`id_tax` = odt.`id_tax`)
@@ -292,12 +292,17 @@ class OrderInvoiceCore extends ObjectModel
 						'total_price_tax_excl' => 0
 					);
 
+				$ratio = $tax_infos['total_price_tax_excl'] / $this->total_products;
+				$order_reduction_amount = $this->total_discount_tax_excl * $ratio;
+
 				$tmp_tax_infos[$tax_infos['rate']]['total_amount'] += $tax_infos['total_amount'];
 				$tmp_tax_infos[$tax_infos['rate']]['name'] = $tax_infos['name'];
-				$tmp_tax_infos[$tax_infos['rate']]['total_price_tax_excl'] += $tax_infos['total_price_tax_excl'];
+				$tmp_tax_infos[$tax_infos['rate']]['total_price_tax_excl'] += ($tax_infos['total_price_tax_excl'] - $order_reduction_amount);
 			}
 		}
 
+
+
 		return $tmp_tax_infos;
 	}