diff --git a/app/models/spree/shipping_method.rb b/app/models/spree/shipping_method.rb
index 3105c11127..b675e8fa1e 100644
--- a/app/models/spree/shipping_method.rb
+++ b/app/models/spree/shipping_method.rb
@@ -109,7 +109,7 @@ module Spree
     end
 
     def init
-      self.calculator ||= ::Calculator::None.new
+      self.calculator ||= ::Calculator::None.new if new_record?
     end
 
     private