diff --git a/ultron/objective/models.py b/ultron/objective/models.py
index 95b7d14f25..5a4361877a 100644
--- a/ultron/objective/models.py
+++ b/ultron/objective/models.py
@@ -235,12 +235,14 @@ class Routine(Educative):
 
     @staticmethod
     def max_even_if_none(value_1, value_2):
+        """
+        """
         if value_1 is not None and value_2 is not None:
             if value_1 > value_2:
                 return value_1
             else:
                 return value_2
-        return None
+        return 0
 
     def compute_informations(self):
         """
@@ -269,22 +271,22 @@ class Routine(Educative):
                 is_competitive = False
 
             # Age boy computing
-            age_boy_with_help = max_even_if_none(skill.age_boy_with_help, age_boy_with_help)
-            age_boy_without_help = max_even_if_none(
+            age_boy_with_help = self.max_even_if_none(skill.age_boy_with_help, age_boy_with_help)
+            age_boy_without_help = self.max_even_if_none(
                 skill.age_boy_without_help,
                 age_boy_without_help
             )
-            age_boy_chained = max_even_if_none(skill.age_boy_chained, age_boy_chained)
-            age_boy_masterised = max_even_if_none(skill.age_boy_masterised, age_boy_masterised)
+            age_boy_chained = self.max_even_if_none(skill.age_boy_chained, age_boy_chained)
+            age_boy_masterised = self.max_even_if_none(skill.age_boy_masterised, age_boy_masterised)
 
             # Age girl computing
-            age_girl_with_help = max_even_if_none(skill.age_girl_with_help, age_girl_with_help)
-            age_girl_without_help = max_even_if_none(
+            age_girl_with_help = self.max_even_if_none(skill.age_girl_with_help, age_girl_with_help)
+            age_girl_without_help = self.max_even_if_none(
                 skill.age_girl_without_help,
                 age_girl_without_help
             )
-            age_girl_chained = max_even_if_none(skill.age_girl_chained, age_girl_chained)
-            age_girl_masterised = max_even_if_none(skill.age_girl_masterised, age_girl_masterised)
+            age_girl_chained = self.max_even_if_none(skill.age_girl_chained, age_girl_chained)
+            age_girl_masterised = self.max_even_if_none(skill.age_girl_masterised, age_girl_masterised)
 
 
         if self.skill_links.all().count() != 10: