diff --git a/apps/web/process/leasing-object/reactions/common.ts b/apps/web/process/leasing-object/reactions/common.ts
index 0a20f97..237fc3d 100644
--- a/apps/web/process/leasing-object/reactions/common.ts
+++ b/apps/web/process/leasing-object/reactions/common.ts
@@ -261,4 +261,15 @@ export default function commonReactions({ store, apolloClient }: ReactionsContex
       $calculation.element('selectConfiguration').setOptions(normalizeOptions(evo_equipments));
     }
   );
+
+  reaction(
+    () => $calculation.element('cbxLeaseObjectUsed').getValue(),
+    (leaseObjectUsed) => {
+      if (leaseObjectUsed) {
+        $calculation.element('tbxLeaseObjectCount').setValue(1).block();
+      } else {
+        $calculation.element('tbxLeaseObjectCount').unblock();
+      }
+    }
+  );
 }