diff --git a/sync_manager.py b/sync_manager.py
index 6f76db8e..68bd17f4 100644
--- a/sync_manager.py
+++ b/sync_manager.py
@@ -107,7 +107,7 @@ class SyncManager:
         self.logger.info(f"{len(self.d365_df)} gültige Datensätze aus D365 geladen, {len(self.gsheet_df)} gültige Datensätze im Google Sheet.")
         return True
 
-    def run_sync(self):
+def run_sync(self):
         """Führt den gesamten Synchronisationsprozess aus."""
         if not self._load_data(): return
             
@@ -140,10 +140,10 @@ class SyncManager:
         
         if existing_ids:
             d365_indexed = self.d365_df.set_index('CRM ID')
-            gsheet_indexed = self.gsheet_df.set_index('CRM ID')
+            gsheet_to_update_df = self.gsheet_df[self.gsheet_df['CRM ID'].isin(existing_ids)]
 
-            for row_idx, gsheet_row in gsheet_indexed.iterrows():
-                crm_id = gsheet_row.name
+            for original_row_index, gsheet_row in gsheet_to_update_df.iterrows():
+                crm_id = gsheet_row['CRM ID']
                 if crm_id not in d365_indexed.index: continue
                 d365_row = d365_indexed.loc[crm_id]
                 
@@ -155,26 +155,18 @@ class SyncManager:
                     
                     is_different = False
                     
-                    # --- FINALE, KORREKTE PRÜFLOGIK-STRUKTUR ---
                     if gsheet_col == 'CRM Land':
                         translated_d365_val = Config.COUNTRY_CODE_MAP.get(d365_val.lower(), d365_val)
                         if translated_d365_val.lower() != gsheet_val.lower():
                             is_different = True
-                    
                     elif gsheet_col == 'CRM Anzahl Techniker':
-                        if d365_val == '-1' and gsheet_val == '':
-                            pass # Explizit nichts tun, sie sind gleich
-                        elif d365_val != gsheet_val:
-                            is_different = True
-                    
+                        if d365_val == '-1' and gsheet_val == '': pass
+                        elif d365_val != gsheet_val: is_different = True
                     elif gsheet_col == 'CRM Branche':
                         if gsheet_row['Chat Vorschlag Branche'] == '' and d365_val != gsheet_val:
                             is_different = True
-                    
-                    else: # Standard-Vergleich für alle anderen Spalten
-                        if d365_val != gsheet_val:
-                            is_different = True
-                    # --- ENDE DER PRÜFLOGIK-STRUKTUR ---
+                    else:
+                        if d365_val != gsheet_val: is_different = True
 
                     if is_different:
                         row_updates[gsheet_col] = d365_val
@@ -195,7 +187,7 @@ class SyncManager:
                 if needs_reeval: row_updates["ReEval Flag"] = "x"
 
                 if row_updates:
-                    sheet_row_number = row_idx + self.sheet_handler._header_rows + 1
+                    sheet_row_number = original_row_index + self.sheet_handler._header_rows + 1
                     for col_name, value in row_updates.items():
                          updates_to_batch.append({ "range": f"{COLUMN_MAP[col_name]['Titel']}{sheet_row_number}", "values": [[value]] })