diff --git a/li.strolch.model/src/main/java/li/strolch/model/ModelHelper.java b/li.strolch.model/src/main/java/li/strolch/model/ModelHelper.java
index 433e07cd1..8eeeff3a9 100644
--- a/li.strolch.model/src/main/java/li/strolch/model/ModelHelper.java
+++ b/li.strolch.model/src/main/java/li/strolch/model/ModelHelper.java
@@ -22,7 +22,7 @@ public class ModelHelper {
 		if (src.hasParameter(bagId, paramId) && !src.getStringP(bagId, paramId).isEmpty()) {
 			StringParameter existingBillingIdP = src.getStringP(bagId, paramId);
 			if (!dst.hasParameter(bagId, paramId)) {
-				dst.addParameter(existingBillingIdP.getClone());
+				dst.addParameter(bagId, existingBillingIdP.getClone());
 			} else if (dst.getStringP(bagId, paramId).isEmpty()) {
 				dst.setString(bagId, paramId, existingBillingIdP.getValue());
 			}