diff --git a/install-dev/upgrade/php/generate_tax_rules.php b/install-dev/upgrade/php/generate_tax_rules.php
index 4091f21c4..e3e60deb9 100644
--- a/install-dev/upgrade/php/generate_tax_rules.php
+++ b/install-dev/upgrade/php/generate_tax_rules.php
@@ -27,21 +27,23 @@
 
 function generate_tax_rules()
 {
-	$ps_lang_default = Db::getInstance()->getValue('SELECT value FROM `'._DB_PREFIX_.'configuration`
-		WHERE name="PS_LANG_DEFAULT"');
-	$taxes = Db::getInstance('SELECT * from `'._DB_PREFIX_.'tax` WHERE active = 1');
+	$res = true;
+	$taxes = Db::getInstance()->executeS('SELECT * from `'._DB_PREFIX_.'tax` WHERE active = 1');
+
+	// if no tax found, nothing to do, return true
+	if (!is_array($taxes))
+		return true;
 
 	foreach ($taxes AS $tax)
 	{
-		$insert = '';
 		$id_tax = $tax['id_tax'];
 		$row = array(
 			'active' => 1,
-			'id_tax' => $id_tax,
+			'id_tax_rules_group' => $id_tax,
 			'name' => 'Rule '.$tax['rate'].'%',
 		);
-		Db::getInstance()->insert('category_group', $row);
-		$id_tax_rules_group = Db::getInstance()->insert_id;
+		$res &= Db::getInstance()->AutoExecute(_DB_PREFIX_.'tax_rules_group', $row, 'INSERT');
+		$id_tax_rules_group = Db::getInstance()->insert_id();
 
 
 		$countries = Db::getInstance()->executeS('
@@ -54,64 +56,58 @@ function generate_tax_rules()
 		{
 			foreach ($countries AS $country)
 			{
-					 $res = Db::getInstance()->execute('
-					 INSERT INTO `'._DB_PREFIX_.'tax_rule` (`id_tax_rules_group`, `id_country`, `id_state`, `state_behavior`, `id_tax`)
-					 VALUES (
-					 '.(int)$id_tax_rules_group.',
-					 '.(int)$country['id_country'].',
-					 0,
-					 0,
-					 '.(int)$id_tax.
-					 ')');
-
+				$res &= Db::getInstance()->execute('INSERT INTO `'._DB_PREFIX_.'tax_rule` 
+					(`id_tax_rules_group`, `id_country`, `id_state`, `state_behavior`, `id_tax`)
+					VALUES 
+					('.$id_tax_rules_group.', '.(int)$country['id_country'].', 0, 0, '.(int)$id_tax. ')');
 			}
 		}
 
 		$states = Db::getInstance()->executeS('
 		SELECT * FROM `'._DB_PREFIX_.'states s
 		LEFT JOIN `'._DB_PREFIX_.'tax_state ts ON (ts.`id_state` = s.`id_state`)
-		WHERE `id_tax` = '.(int)$id_tax
-		);
+		WHERE `id_tax` = '.(int)$id_tax);
 
 		if ($states)
 		{
 			foreach ($states AS $state)
 			{
-			    if (!in_array($state['tax_behavior'], array(PS_PRODUCT_TAX, PS_STATE_TAX, PS_BOTH_TAX)))
-			        $tax_behavior = PS_PRODUCT_TAX;
-			    else
-			        $tax_behavior = $state['tax_behavior'];
-
-					 $res = Db::getInstance()->execute('
-					 INSERT INTO `'._DB_PREFIX_.'tax_rule` (`id_tax_rules_group`, `id_country`, `id_state`, `state_behavior`, `id_tax`)
-					 VALUES (
-					 '.(int)$id_tax_rules_group.',
-					 '.(int)$state['id_country'].',
-					 '.(int)$state['id_state'].',
-					 '.(int)$tax_behavior.',
-					 '.(int)$id_tax.
-					 ')');
+				if (!in_array($state['tax_behavior'], array(PS_PRODUCT_TAX, PS_STATE_TAX, PS_BOTH_TAX)))
+					$tax_behavior = PS_PRODUCT_TAX;
+				else
+					$tax_behavior = $state['tax_behavior'];
+				$res &= Db::getInstance()->execute('
+					INSERT INTO `'._DB_PREFIX_.'tax_rule`
+					(`id_tax_rules_group`, `id_country`, `id_state`, `state_behavior`, `id_tax`)
+					VALUES (
+					'.$id_tax_rules_group.',
+				 	'.(int)$state['id_country'].',
+	 					'.(int)$state['id_state'].',
+				 '.(int)$tax_behavior.',
+				 '.(int)$id_tax.
+				 ')');
 			}
 		}
 
-		Db::getInstance()->execute('
+		$res &= Db::getInstance()->execute('
 		UPDATE `'._DB_PREFIX_.'product`
-		SET `id_tax_rules_group` = '.(int)$id_tax_rules_group.'
+		SET `id_tax_rules_group` = '.$id_tax_rules_group.'
 		WHERE `id_tax` = '.(int)$id_tax
 		);
 
-		Db::getInstance()->execute('
+		$res &= Db::getInstance()->execute('
 		UPDATE `'._DB_PREFIX_.'carrier`
-		SET `id_tax_rules_group` = '.(int)$id_tax_rules_group.'
+		SET `id_tax_rules_group` = '.$id_tax_rules_group.'
 		WHERE `id_tax` = '.(int)$id_tax
 		);
 
-
-	$socolissimo_overcost_tax = Db::getInstance()->getValue('SELECT value FROM `'._DB_PREFIX_.'configuration`
-		WHERE name="SOCOLISSIMO_OVERCOST_TAX"');
+		$socolissimo_overcost_tax = Db::getInstance()->getValue('SELECT value 
+			FROM `'._DB_PREFIX_.'configuration`
+			WHERE name="SOCOLISSIMO_OVERCOST_TAX"');
 		if ($socolissimo_overcost_tax == $id_tax)
-			$res &= Db::getInstance()->getValue('REPLACE INTO `'._DB_PREFIX_.'configuration`
-				(name, value) VALUES ("PS_POUET", "'.$id_tax_rules_group.'"');
+			$res &= Db::getInstance()->getValue('UPDATE `'._DB_PREFIX_.'configuration`
+			set value="'.$id_tax_rules_group.'" WHERE name="SOCOLISSIMO_OVERCOST_TAX"');
 	}
+	return $res;
 }