diff --git a/install-dev/upgrade/php/migrate_orders.php b/install-dev/upgrade/php/migrate_orders.php
index 6929bd07d..96160fa4b 100644
--- a/install-dev/upgrade/php/migrate_orders.php
+++ b/install-dev/upgrade/php/migrate_orders.php
@@ -95,7 +95,8 @@ function migrate_orders()
 			$reduction_amount_tax_incl = (float)$products['reduction_amount'];
 
 			// cart::getTaxesAverageUsed equivalent
-			$sum_total_products += $products['total_wt'];
+			$sum_total_products += $products['total_price'];
+			
 			$sum_tax_amount += $products['total_wt'] - $products['total_price'];
 
 			$order_details['reduction_amount_tax_incl'] = $reduction_amount_tax_incl;
@@ -119,12 +120,11 @@ function migrate_orders()
 
 		$average_tax_used = 1;
 		if ($sum_total_products > 0)
-			$average_tax_used +=  ($sum_tax_amount / $sum_total_products) * 0.01;
-
+			$average_tax_used +=  $sum_tax_amount / $sum_total_products;
+		$average_tax_used = round($average_tax_used, 4);
 		$carrier_tax_rate = 1 + ((float)$order['carrier_tax_rate'] / 100);
 
 		$total_discount_tax_excl = $order['total_discounts'] / $average_tax_used;
-
 		$order['total_discounts_tax_incl'] = (float)$order['total_discounts'];
 		$order['total_discounts_tax_excl'] = (float)$total_discount_tax_excl;
 
@@ -321,5 +321,4 @@ function mo_setProductPrices($row, $tax_calculation_method)
     $row['total_price'] = $row['product_quantity'] * $row['product_price'];
 
     return $row;
-}
-
+}
\ No newline at end of file