diff --git a/dyndomain b/dyndomain
index 24318e4..0c24ff8 100755
--- a/dyndomain
+++ b/dyndomain
@@ -159,17 +159,18 @@ def process_zone(zone, stamp, grace_period, sync_zone):
     update = { 'add': [], 'delete': [] }
     for prot in zone:
         for name in zone[prot]:
-            add = False
+            active = False
             for addr in zone[prot][name]:
                 e = zone[prot][name][addr]
-                if e['first'] == stamp and not sync_zone:
+                if e['first'] == stamp:
                     update['add'].append([prot, name, addr])
-                    add = True
+                if e['last'] == stamp:
+                    active = True
             for addr in zone[prot][name]:
                 e = zone[prot][name][addr]
-                if add and e['last'] < stamp:
+                if active and e['last'] < stamp:
                     update['delete'].append([prot, name, addr])
-                elif not add and stamp - e['last'] > grace_period:
+                elif not active and stamp - e['last'] > grace_period:
                     update['delete'].append([prot, name, addr])
                 elif sync_zone:
                     update['add'].append([prot, name, addr])