diff --git a/spec/OnDemandServices b/spec/OnDemandServices
index 33014c7b..5c87ec71 100644
--- a/spec/OnDemandServices
+++ b/spec/OnDemandServices
@@ -173,8 +173,10 @@ In case of a shallow integration the OSDM flow ends here.
 
                   in case of post-payment: new ContinuousServiceBookingPart added in the booking:
                     - including the price                     (alternative: update existing booking part and extend the state model)
+                    - fulfillment documents on the pricing / calculation of costs
                   in case of pre-payment: 
                     - including a new refund on the existing ContinuousServiceBookingPart
+                    - fulfillment documents on the pricing / calculation of costs
 
 
 reembourcement: