diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index cc7d442..37b01e3 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -155,14 +155,15 @@
 	return con;
 }
 
-struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token)
+struct bsc_config *bsc_config_alloc(struct bsc_nat *nat, const char *token,
+				    unsigned int number)
 {
 	struct bsc_config *conf = talloc_zero(nat, struct bsc_config);
 	if (!conf)
 		return NULL;
 
 	conf->token = talloc_strdup(conf, token);
-	conf->nr = nat->num_bsc;
+	conf->nr = number;
 	conf->nat = nat;
 	conf->max_endpoints = 32;
 	conf->paging_group = PAGIN_GROUP_UNASSIGNED;
@@ -205,6 +206,8 @@
 	llist_del(&cfg->entry);
 	rate_ctr_group_free(cfg->stats.ctrg);
 	talloc_free(cfg);
+	cfg->nat->num_bsc--;
+	OSMO_ASSERT(cfg->nat->num_bsc >= 0)
 }
 
 static void _add_lac(void *ctx, struct llist_head *list, int _lac)