diff --git a/project/creditor/models.py b/project/creditor/models.py
index 7315ed5c..e23cf429 100644
--- a/project/creditor/models.py
+++ b/project/creditor/models.py
@@ -125,17 +125,22 @@ def in_timescope(self, timescope=None):
         scope_start_ts, scope_end_ts = self.resolve_timescope(timescope)
         scope_start = scope_start_ts.date()
         scope_end = scope_end_ts.date()
+
         return (self.start <= scope_end
                 and (not self.end
-                     or self.end >= scope_end))
+                     or self.end >= scope_start))
 
     @transaction.atomic()
     def transaction_exists(self, timescope=None):
         start, end = self.resolve_timescope(timescope)
         uid_source = self.make_uid_source(timescope)
         uid = hashlib.sha1(uid_source.encode('UTF-8')).hexdigest()
+        # Check for uid match
+        if Transaction.objects.filter(unique_id=uid).count():
+            return True
+        # check for time based match
         qs = Transaction.objects.filter(
-            owner=self.owner, tag=self.tag, unique_id=uid, stamp__gte=start, stamp__lte=end
+            owner=self.owner, tag=self.tag, stamp__gte=start, stamp__lte=end
         )
         if qs.count():
             return True
diff --git a/project/creditor/tests/test_recurring.py b/project/creditor/tests/test_recurring.py
index c0fabe9b..93ed0ba8 100644
--- a/project/creditor/tests/test_recurring.py
+++ b/project/creditor/tests/test_recurring.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 import calendar
 import datetime
+from django.utils import timezone
 
 import pytest
 import pytz
@@ -10,10 +11,11 @@
 def year_start_end(timescope=None):
     if timescope is None:
         timescope = datetime.datetime.now()
-    start = start = datetime.datetime(timescope.year, 1, 1).date()
+    start = datetime.datetime(timescope.year, 1, 1).date()
     end = datetime.datetime(start.year, 12, calendar.monthrange(start.year, 12)[1]).date()
     return (start, end)
 
+
 def quarter_start_end(timescope=None):
     if timescope is None:
         timescope = datetime.datetime.now()
@@ -29,9 +31,10 @@ def quarter_start_end(timescope=None):
     end = datetime.datetime(start.year, end_month, calendar.monthrange(start.year, end_month)[1]).date()
     return (start, end)
 
+
 def month_start_end(timescope=None):
     if timescope is None:
-        timescope = datetime.datetime.now()
+        timescope = timezone.now()
     start = datetime.datetime(timescope.year, timescope.month, 1).date()
     end = datetime.datetime(start.year, start.month, calendar.monthrange(start.year, start.month)[1]).date()
     return (start, end)
@@ -39,47 +42,65 @@ def month_start_end(timescope=None):
 
 @pytest.mark.django_db
 def test_yearly_in_scope_with_end():
-    now = datetime.datetime.now()
+    now = timezone.now()
     start, end = year_start_end(now)
-    t = MembershipfeeFactory(start=start, end=end)
-    assert t.in_timescope(now)
+    for x in range(5):
+        t = MembershipfeeFactory(start=start, end=end)
+        assert t.in_timescope(now)
+        ret1 = t.conditional_add_transaction(now)
+        assert ret1
+        ret2 = t.conditional_add_transaction(now)
+        assert not ret2
 
 
 @pytest.mark.django_db
 def test_yearly_in_scope_without_end():
-    now = datetime.datetime.now()
+    now = timezone.now()
     start, end = year_start_end(now - datetime.timedelta(weeks=60))
     end = None
-    t = MembershipfeeFactory(start=start, end=end)
-    assert t.in_timescope(now)
+    for x in range(5):
+        t = MembershipfeeFactory(start=start, end=end)
+        assert t.in_timescope(now)
+        ret1 = t.conditional_add_transaction(now)
+        assert ret1
+        ret2 = t.conditional_add_transaction(now)
+        assert not ret2
 
 
 @pytest.mark.django_db
 def test_yearly_not_in_scope_ended():
-    now = datetime.datetime.now()
+    now = timezone.now()
     start, end = year_start_end(now - datetime.timedelta(weeks=60))
     t = MembershipfeeFactory(start=start, end=end)
     assert not t.in_timescope(now)
+    ret2 = t.conditional_add_transaction(now)
+    assert not ret2
 
 
 @pytest.mark.django_db
 def test_yearly_not_in_scope_notstarted():
-    now = datetime.datetime.now()
+    now = timezone.now()
     start, end = year_start_end(now + datetime.timedelta(weeks=60))
     t = MembershipfeeFactory(start=start, end=end)
     assert not t.in_timescope(now)
+    ret2 = t.conditional_add_transaction(now)
+    assert not ret2
+
 
 @pytest.mark.django_db
 def test_quarterly_in_scope_with_end():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = quarter_start_end(now)
     end += datetime.timedelta(weeks=15)
     t = QuarterlyFactory(start=start, end=end)
     assert t.in_timescope(now)
 
+
 @pytest.mark.django_db
 def test_quarterly_in_scope_without_end():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now - datetime.timedelta(weeks=15))
     end = None
     t = QuarterlyFactory(start=start, end=end)
@@ -87,21 +108,24 @@ def test_quarterly_in_scope_without_end():
 
 @pytest.mark.django_db
 def test_quarterly_not_in_scope_ended():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now - datetime.timedelta(weeks=25))
     t = QuarterlyFactory(start=start, end=end)
     assert not t.in_timescope(now)
 
 @pytest.mark.django_db
 def test_quarterly_not_in_scope_notstarted():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now + datetime.timedelta(weeks=25))
     t = QuarterlyFactory(start=start, end=end)
     assert not t.in_timescope(now)
 
 @pytest.mark.django_db
 def test_monthly_in_scope_with_end():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now)
     end += datetime.timedelta(weeks=6)
     t = KeyholderfeeFactory(start=start, end=end)
@@ -110,7 +134,8 @@ def test_monthly_in_scope_with_end():
 
 @pytest.mark.django_db
 def test_monthly_in_scope_without_end():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now - datetime.timedelta(weeks=6))
     end = None
     t = KeyholderfeeFactory(start=start, end=end)
@@ -119,7 +144,8 @@ def test_monthly_in_scope_without_end():
 
 @pytest.mark.django_db
 def test_monthly_not_in_scope_ended():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now - datetime.timedelta(weeks=10))
     t = KeyholderfeeFactory(start=start, end=end)
     assert not t.in_timescope(now)
@@ -127,7 +153,8 @@ def test_monthly_not_in_scope_ended():
 
 @pytest.mark.django_db
 def test_monthly_not_in_scope_notstarted():
-    now = datetime.datetime.now()
+    now = timezone.now()
+
     start, end = month_start_end(now + datetime.timedelta(weeks=10))
     t = KeyholderfeeFactory(start=start, end=end)
     assert not t.in_timescope(now)