diff --git a/golem_member/data/golem_member_numberconfig_data.xml b/golem_member/data/golem_member_numberconfig_data.xml
index f02373b..e28e165 100644
--- a/golem_member/data/golem_member_numberconfig_data.xml
+++ b/golem_member/data/golem_member_numberconfig_data.xml
@@ -23,6 +23,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
       eval="('golem_numberconfig_isautomatic', '1')" />
     <function model="ir.config_parameter" name="set_param"
       eval="('golem_numberconfig_isperseason', '1')" />
+    <function model="ir.config_parameter" name="set_param"
+      eval="('golem_numberconfig_isfornewmembersonly', '0')" />
     <function model="ir.config_parameter" name="set_param"
       eval="('golem_numberconfig_prefix', '')" />
     <function model="ir.config_parameter" name="set_param"
diff --git a/golem_member/models/golem_member.py b/golem_member/models/golem_member.py
index 5c0ea9c..1341b89 100644
--- a/golem_member/models/golem_member.py
+++ b/golem_member/models/golem_member.py
@@ -193,11 +193,14 @@ class GolemMember(models.Model):
         """ Computes number according to pre-existing number and chosen
         seasons """
         conf = self.env['ir.config_parameter']
+        isauto = conf.get_param('golem_numberconfig_isautomatic') == '1'
+        isperseason = conf.get_param('golem_numberconfig_isperseason') == '1'
+        isfornew = conf.get_param('golem_numberconfig_isfornewmembersonly') == '1'
         for member in self:
-            if conf.get_param('golem_numberconfig_isautomatic') == '0':
+            if not isauto or (isfornew and member.number_manual):
                 member.number = member.number_manual
             else:
-                if conf.get_param('golem_numberconfig_isperseason') == '1':
+                if isperseason:
                     member_num = member.generate_number_perseason()
                 else:
                     member_num = member.generate_number_global()
@@ -282,6 +285,13 @@ class GolemNumberConfig(models.TransientModel):
             self.env['golem.season'].search([]).write({
                 'member_counter': int(self.number_from)
             })
+    @api.multi
+    def apply_nocompute(self):
+        """ Apply new configuration only for new members (keep old numbers) """
+        self.ensure_one()
+        self.apply_config()
+        conf = self.env['ir.config_parameter']
+        conf.set_param('golem_numberconfig_isfornewmembersonly', '1')
 
     @api.multi
     def apply_recompute(self):
@@ -289,6 +299,7 @@ class GolemNumberConfig(models.TransientModel):
         self.ensure_one()
         self.apply_config()
         conf = self.env['ir.config_parameter']
+        conf.set_param('golem_numberconfig_isfornewmembersonly', '0')
         conf.set_param('golem_number_counter', self.number_from)
         self.env['golem.member.number'].search([]).unlink()
         self.env['golem.season'].search([]).write({
diff --git a/golem_member/tests/test_golem_member.py b/golem_member/tests/test_golem_member.py
index aab17e0..4c64978 100644
--- a/golem_member/tests/test_golem_member.py
+++ b/golem_member/tests/test_golem_member.py
@@ -142,7 +142,7 @@ class GolemMemberTestCase(TransactionCase):
         conf = self.member_numberconfig_model.create({'is_automatic': '1',
                                                       'is_per_season': '0',
                                                       'prefix': False})
-        conf.apply_config()
+        conf.apply_nocompute()
         self.assertEqual(self.member1.number, u'M01')
         new_m = self.member_model.create({'lastname': 'NEW',
                                           'firstname': 'Buddy',
@@ -158,7 +158,7 @@ class GolemMemberTestCase(TransactionCase):
                                                       'is_per_season': '0',
                                                       'prefix': False,
                                                       'number_from': 50})
-        conf.apply_config()
+        conf.apply_nocompute()
         self.assertEqual(self.member1.number, u'M01')
         new_m = self.member_model.create({'lastname': 'NEW',
                                           'firstname': 'Buddy',
@@ -168,3 +168,9 @@ class GolemMemberTestCase(TransactionCase):
                                            'season_ids': [self.season_current]})
         self.assertEqual(new_m.number, u'50')
         self.assertEqual(new_m2.number, u'51')
+        # After season changing
+        self.season_next.do_default_season()
+        self.assertEqual(self.member1.number, u'M01')
+        self.assertEqual(new_m.number, u'50')
+        self.member1.season_ids += self.season_next
+        self.assertEqual(self.member1.number, u'M01')
diff --git a/golem_member/views/golem_member_numberconfig_views.xml b/golem_member/views/golem_member_numberconfig_views.xml
index 632cfd5..dc6e250 100644
--- a/golem_member/views/golem_member_numberconfig_views.xml
+++ b/golem_member/views/golem_member_numberconfig_views.xml
@@ -38,7 +38,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
             </group>
           </sheet>
           <footer>
-            <button type="object" name="apply_config"
+            <button type="object" name="apply_nocompute"
               string="Apply for new members" />
             <button type="object" name="apply_recompute"
               string="Apply and recompute all member numbers"