diff --git a/app/controllers/epp/domains_controller.rb b/app/controllers/epp/domains_controller.rb
index c47e0d69f..82eae2105 100644
--- a/app/controllers/epp/domains_controller.rb
+++ b/app/controllers/epp/domains_controller.rb
@@ -142,7 +142,7 @@ class Epp::DomainsController < EppController
   end
 
   def validate_update
-    if params[:parsed_frame].css('chg registrant').present? && params[:parsed_frame].css('legalDocument').blank?
+    if element_count('update > chg > registrant') > 0
       requires('extension > extdata > legalDocument')
     end
 
diff --git a/app/controllers/epp_controller.rb b/app/controllers/epp_controller.rb
index 6d38a5225..8981dcd8f 100644
--- a/app/controllers/epp_controller.rb
+++ b/app/controllers/epp_controller.rb
@@ -75,32 +75,9 @@ class EppController < ApplicationController
     epp_errors.empty?
   end
 
-  def mutually_exclusive(*selectors)
-    present_count = 0
-    selectors.each do |selector|
-      full_selector = [@prefix, selector].join(' ')
-      el = params[:parsed_frame].css(full_selector).first
-      present_count += 1 if el && el.text.present?
-    end
-
-    return if present_count <= 1
-
-    epp_errors << {
-      code: '2306',
-      msg: I18n.t(:are_mutally_exclusive, params: selectors.join(', '))
-    }
-  end
-
   # let's follow grape's validations: https://github.com/intridea/grape/#parameter-validation-and-coercion
   def exactly_one_of(*selectors)
-    present_count = 0
-    selectors.each do |selector|
-      full_selector = [@prefix, selector].join(' ')
-      el = params[:parsed_frame].css(full_selector).first
-      present_count += 1 if el && el.text.present?
-    end
-
-    return if present_count == 1
+    return if element_count(*selectors) == 1
 
     epp_errors << {
       code: '2306',
@@ -108,6 +85,14 @@ class EppController < ApplicationController
     }
   end
 
+  def mutually_exclusive(*selectors)
+    return if element_count(*selectors) <= 1
+    epp_errors << {
+      code: '2306',
+      msg: I18n.t(:mutally_exclusive_params, params: selectors.join(', '))
+    }
+  end
+
   def optional(selector, *validations)
     full_selector = [@prefix, selector].join(' ')
     el = params[:parsed_frame].css(full_selector).first
@@ -121,6 +106,16 @@ class EppController < ApplicationController
     end
   end
 
+  def element_count(*selectors)
+    present_count = 0
+    selectors.each do |selector|
+      full_selector = [@prefix, selector].join(' ')
+      el = params[:parsed_frame].css(full_selector).first
+      present_count += 1 if el && el.text.present?
+    end
+    present_count
+  end
+
   def xml_attrs_present?(ph, attributes) # TODO: THIS IS DEPRECATED AND WILL BE REMOVED IN FUTURE
     attributes.each do |x|
       epp_errors << {
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 15236335a..b14579991 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -500,4 +500,4 @@ en:
   could_not_determine_object_type_check_xml_format_and_namespaces: 'Could not determine object type. Check XML format and namespaces.'
   unknown_expiry_relative_pattern: 'Expiry relative must be compatible to ISO 8601'
   unknown_expiry_absolute_pattern: 'Expiry absolute must be compatible to ISO 8601'
-  are_mutally_exclusive: '%{params} are mutually exclusive'
+  mutally_exclusive_params: 'Mutually exclusive parameters: %{params}'
diff --git a/spec/epp/domain_spec.rb b/spec/epp/domain_spec.rb
index e810585ba..355c06f09 100644
--- a/spec/epp/domain_spec.rb
+++ b/spec/epp/domain_spec.rb
@@ -629,7 +629,7 @@ describe 'EPP Domain', epp: true do
         })
 
       response = epp_plain_request(xml, :xml)
-      response[:msg].should == 'keyData, dsData are mutually exclusive'
+      response[:msg].should == 'Mutually exclusive parameters: keyData, dsData'
       response[:result_code].should == '2306'
     end
   end