diff --git a/library/NS_Emulation.ttcnpp b/library/NS_Emulation.ttcnpp
index ca44a02..6d8113c 100644
--- a/library/NS_Emulation.ttcnpp
+++ b/library/NS_Emulation.ttcnpp
@@ -310,30 +310,16 @@
 			/* add index to list of unblocked NSVCs */
 			if (not ischosen(g_nsvcs[i].cfg.provider.ip) or
 			    g_nsvcs[i].cfg.provider.ip.signalling_weight > 0) {
-				g_unblocked_nsvcs_sig := g_unblocked_nsvcs_sig & {i};
+				ro_integer_add_unique(g_unblocked_nsvcs_sig, i);
 			}
 			if (not ischosen(g_nsvcs[i].cfg.provider.ip) or
 			    g_nsvcs[i].cfg.provider.ip.data_weight > 0) {
-				g_unblocked_nsvcs_data := g_unblocked_nsvcs_data & {i};
+				ro_integer_add_unique(g_unblocked_nsvcs_data, i);
 			}
 		} else if (g_nsvcs[i].state == NSVC_S_ALIVE_UNBLOCKED and state != NSVC_S_ALIVE_UNBLOCKED) {
 			/* remove index to list of unblocked NSVCs */
-			var Osmocom_Types.ro_integer new_unblocked_nsvcs_sig := {};
-			for (var integer j := 0; j < lengthof(g_unblocked_nsvcs_sig); j := j+1) {
-				if (g_unblocked_nsvcs_sig[j] != i) {
-					new_unblocked_nsvcs_sig := new_unblocked_nsvcs_sig & {j};
-				}
-			}
-			g_unblocked_nsvcs_sig := new_unblocked_nsvcs_sig;
-
-			var Osmocom_Types.ro_integer new_unblocked_nsvcs_data := {};
-			for (var integer j := 0; j < lengthof(g_unblocked_nsvcs_data); j := j+1) {
-				if (g_unblocked_nsvcs_data[j] != i) {
-					new_unblocked_nsvcs_data := new_unblocked_nsvcs_data & {j};
-				}
-			}
-			g_unblocked_nsvcs_data := new_unblocked_nsvcs_data;
-
+			ro_integer_del(g_unblocked_nsvcs_sig, i);
+			ro_integer_del(g_unblocked_nsvcs_data, i);
 		}
 		g_nsvcs[i].state := state;
 	}