Gifts are doubled

Bug: if you choose a gift certificate from your codes and this one doesn't cover your checkout value, the system deduces 2 time the same certificate.

This is my patch:

diff --git a/uc_gift_certificate.module b/uc_gift_certificate.module
index f1f0cf3..5ebc0a2 100644
--- a/uc_gift_certificate.module
+++ b/uc_gift_certificate.module
@@ -1526,11 +1526,14 @@ function uc_gift_certificate_attach(&$order, $certificate) {
  */
 function uc_gift_certificate_calculate_deduction(&$order, $line_items = FALSE) { // Get order line items.
   $total_certificates = 0;
-
+  $deduct = 0;
   // If we are adding a new certificate at checkout, handle that first.
   if (is_object($order->uc_gift_certificate_added)) {
   //  $new_certificate = $order->uc_gift_certificate_added;
     $total_certificates += $order->uc_gift_certificate_added->remaining_value;
+    if($order->uc_gift_certificate_added->uid == $order->uid ) {
+        $deduct = $order->uc_gift_certificate_added->remaining_value;
+    }
   //  $order->uc_gift_certificate_used[$new_certificate->certificate_id] = $new_certificate;
     //uc_order_line_item_add($order->order_id, 'gift_certificate', t('Gift Certificates'), -abs(floatval($new_certificate['remaining_value'])), 10, $certificate_data);
   }
@@ -1538,7 +1541,7 @@ function uc_gift_certificate_calculate_deduction(&$order, $line_items = FALSE) {
     $total_deducted = 0;
 
     // @todo: Refactor this into the $order->uc_gift_certificate_used array somehow, so it's one less function call
-    $total_certificates += uc_gift_certificate_total($order->uid);
+    $total_certificates += (uc_gift_certificate_total($order->uid) - $deduct );
 
     $order_total = uc_order_get_total($order); // Order total may not be correct, so we need to recalculate it.