diff --git a/app/controllers/admin/enterprise_fees_controller.rb b/app/controllers/admin/enterprise_fees_controller.rb
index 2a3c4cfd77..d74d1e7c22 100644
--- a/app/controllers/admin/enterprise_fees_controller.rb
+++ b/app/controllers/admin/enterprise_fees_controller.rb
@@ -84,12 +84,7 @@ module Admin
         collection_attributes: [
           :id, :enterprise_id, :fee_type, :name, :tax_category_id,
           :inherits_tax_category, :calculator_type,
-          { calculator_attributes:
-              [:id, :preferred_currency, :preferred_amount, :preferred_flat_percent,
-               :preferred_minimal_amount, :preferred_normal_amount, :preferred_discount_amount,
-               :preferred_unit_from_list, :preferred_per_unit, :preferred_first_item,
-               :preferred_additional_item, :preferred_max_items]
-          }
+          { calculator_attributes: PermittedAttributes::Calculator.attributes }
         ]
       )
     end
diff --git a/app/services/permitted_attributes/calculator.rb b/app/services/permitted_attributes/calculator.rb
new file mode 100644
index 0000000000..ba5385d01c
--- /dev/null
+++ b/app/services/permitted_attributes/calculator.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module PermittedAttributes
+  class Calculator
+    def self.attributes
+      [
+        :id, :preferred_currency, :preferred_amount, :preferred_flat_percent,
+        :preferred_minimal_amount, :preferred_normal_amount, :preferred_discount_amount,
+        :preferred_unit_from_list, :preferred_per_unit, :preferred_first_item,
+        :preferred_additional_item, :preferred_max_items
+      ]
+    end
+  end
+end