diff --git a/lib/validates_timeliness/extensions/multiparameter_attribute.rb b/lib/validates_timeliness/extensions/multiparameter_attribute.rb
index b1278521..23160354 100644
--- a/lib/validates_timeliness/extensions/multiparameter_attribute.rb
+++ b/lib/validates_timeliness/extensions/multiparameter_attribute.rb
@@ -42,8 +42,8 @@ def validate_multiparameter_date_values(set_values)
       end
 
       def read_value_with_timeliness
-        @column = object.class.reflect_on_aggregation(name.to_sym) || object.column_for_attribute(name)
-        klass   = column.klass
+        @cast_type = object.type_for_attribute(name)
+        klass = cast_type.klass
 
         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? }
diff --git a/lib/validates_timeliness/validator.rb b/lib/validates_timeliness/validator.rb
index 806dbe2b..289f86ec 100644
--- a/lib/validates_timeliness/validator.rb
+++ b/lib/validates_timeliness/validator.rb
@@ -43,9 +43,10 @@ def initialize(options)
 
       @restrictions_to_check = RESTRICTIONS.keys & options.keys
       super
+      setup_timeliness_validated_attributes(options[:class]) if options[:class]
     end
 
-    def setup(model)
+    def setup_timeliness_validated_attributes(model)
       if model.respond_to?(:timeliness_validated_attributes)
         model.timeliness_validated_attributes ||= []
         model.timeliness_validated_attributes |= @attributes