diff --git a/model/invoice.php b/model/invoice.php
index 153adde..7e2cd7e 100644
--- a/model/invoice.php
+++ b/model/invoice.php
@@ -172,7 +172,7 @@ public function makeNew(){
         if(!empty($this->order) && is_object($this->order))
         {
             $this->invoice_number = $d->format('Ym') . '-' . $this->order->get_id() . '-R';
-            $this->offer_number = $d->format('Ym') . '-' . $this->order->get_id() . '-R';
+            $this->offer_number = $d->format('Ym') . '-' . $this->order->get_id() . '-A';
             $this->wc_order_id = $this->order->get_id();
             $this->customer_id = $this->order->get_customer_id();
         } else {