diff --git a/lib/validates_timeliness/extensions/attribute_assignment.rb b/lib/validates_timeliness/extensions/attribute_assignment.rb
index 13d269ad..ed91e186 100644
--- a/lib/validates_timeliness/extensions/attribute_assignment.rb
+++ b/lib/validates_timeliness/extensions/attribute_assignment.rb
@@ -16,14 +16,15 @@ def execute_callstack_for_multiparameter_attributes_with_timeliness(callstack)
         errors = []
         callstack.each do |name, values_with_empty_parameters|
           begin
-            send(name + "=", MultipleAttribute.new(self, name, values_with_empty_parameters))
+            send("#{name}=", self.class::MultiparameterAttribute.new(self, name, values_with_empty_parameters).read_value)
           rescue => ex
             values = values_with_empty_parameters.is_a?(Hash) ? values_with_empty_parameters.values : values_with_empty_parameters
-            errors << ActiveRecord::AttributeAssignmentError.new("error on assignment #{values.inspect} to #{name}", ex, name)
+            errors << ActiveRecord::AttributeAssignmentError.new("error on assignment #{values.inspect} to #{name} (#{ex.message})", ex, name)
           end
         end
         unless errors.empty?
-          raise ActiveRecord::MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes"
+          error_descriptions = errors.map { |ex| ex.message }.join(",")
+          raise ActiveRecord::MultiparameterAssignmentErrors.new(errors), "#{errors.size} error(s) on assignment of multiparameter attributes [#{error_descriptions}]"
         end
       end
 
diff --git a/lib/validates_timeliness/extensions/multiparameter_attribute.rb b/lib/validates_timeliness/extensions/multiparameter_attribute.rb
index 62b7b0b4..b1278521 100644
--- a/lib/validates_timeliness/extensions/multiparameter_attribute.rb
+++ b/lib/validates_timeliness/extensions/multiparameter_attribute.rb
@@ -14,48 +14,49 @@ module MultiparameterAttribute
 
 #      private
 
-      def invalid_multiparameter_date_or_time_as_string(values)
-        value =  [values[0], *values[1..2].map {|s| s.to_s.rjust(2,"0")} ].join("-")
-        value += ' ' + values[3..5].map {|s| s.to_s.rjust(2, "0") }.join(":") unless values[3..5].empty?
+      def invalid_multiparameter_date_or_time_as_string(set_values)
+        value =  [set_values[0], *set_values[1..2].map {|s| s.to_s.rjust(2,"0")} ].join("-")
+        value += ' ' + set_values[3..5].map {|s| s.to_s.rjust(2, "0") }.join(":") unless set_values[3..5].empty?
         value
       end
 
-      def instantiate_time_object_with_timeliness(name, values)
-        validate_multiparameter_date_values(values) {
-          instantiate_time_object_without_timeliness(name, values)
+      def instantiate_time_object_with_timeliness(set_values)
+        validate_multiparameter_date_values(set_values) {
+          instantiate_time_object_without_timeliness(set_values)
         }
       end
 
-      def instantiate_date_object(name, values)
-        validate_multiparameter_date_values(values) {
-          Date.new(*values)
+      def instantiate_date_object(set_values)
+        validate_multiparameter_date_values(set_values) {
+          Date.new(*set_values)
         }
       end
 
       # Yield if date values are valid
-      def validate_multiparameter_date_values(values)
-        if values[0..2].all?{ |v| v.present? } && Date.valid_civil?(*values[0..2])
+      def validate_multiparameter_date_values(set_values)
+        if set_values[0..2].all?{ |v| v.present? } && Date.valid_civil?(*set_values[0..2])
           yield
         else
-          invalid_multiparameter_date_or_time_as_string(values)
+          invalid_multiparameter_date_or_time_as_string(set_values)
         end
       end
 
-      def read_value_with_timeliness(name, values_from_param)
-        klass = (self.class.reflect_on_aggregation(name.to_sym) || column_for_attribute(name)).klass
-        values = values_from_param.is_a?(Hash) ? values_from_param.to_a.sort_by(&:first).map(&:last) : values_from_param
+      def read_value_with_timeliness
+        @column = object.class.reflect_on_aggregation(name.to_sym) || object.column_for_attribute(name)
+        klass   = column.klass
 
-        if values.empty? || values.all?{ |v| v.nil? }
+        set_values = values.is_a?(Hash) ? values.to_a.sort_by(&:first).map(&:last) : values
+        if set_values.empty? || set_values.all?{ |v| v.nil? }
           nil
         elsif klass == Time
-          instantiate_time_object(name, values)
+          instantiate_time_object(set_values)
         elsif klass == Date
-          instantiate_date_object(name, values)
+          instantiate_date_object(set_values)
         else
           if respond_to?(:read_other_parameter_value)
-            read_date_parameter_value(name, values_from_param)
+            read_date_parameter_value(name, values)
           else
-            klass.new(*values)
+            klass.new(*set_values)
           end
         end
       end