diff --git a/library/RAW_NS.ttcnpp b/library/RAW_NS.ttcnpp
index 8f986e4..42efb7d 100644
--- a/library/RAW_NS.ttcnpp
+++ b/library/RAW_NS.ttcnpp
@@ -408,11 +408,11 @@
 }
 
 /* perform inbound SNS-CHANGE-WEIGHT procedure */
-function f_incoming_sns_chg_weight(template (omit) NsCause cause := omit, integer idx := 0)
+function f_incoming_sns_chg_weight(integer idx_chg := 0, template (omit) NsCause cause := omit, integer idx := 0)
 runs on RAW_NS_CT {
 	log("f_incoming_sns_chg_weight(idx=", idx, ")");
 	var PDU_NS rx;
-	var NSVCConfiguration nsvc_cfg := g_nsconfig.nsvc[idx];
+	var NSVCConfiguration nsvc_cfg := g_nsconfig.nsvc[idx_chg];
 
 	if (nsvc_cfg.provider.ip.address_family == AF_INET) {
 		var template IP4_Elements v4_elem := { tr_SNS_IPv4(nsvc_cfg.provider.ip.remote_ip,