diff --git a/src/action/addusedtime2.ts b/src/action/addusedtime2.ts
index 82ad7c4..7c6af09 100644
--- a/src/action/addusedtime2.ts
+++ b/src/action/addusedtime2.ts
@@ -171,7 +171,7 @@ class AddUsedTimeActionItemSessionDurationLimitSlot {
     this.pause = pause
   }
 
-  serialize = () => [ this.start, this.end ]
+  serialize = () => [ this.start, this.end, this.duration, this.pause ]
 
   static parse = ([ start, end, duration, pause ]: [number, number, number, number]) => new AddUsedTimeActionItemSessionDurationLimitSlot({ start, end, duration, pause })
 }