diff --git a/openbsc/src/mgcp/mgcp_network.c b/openbsc/src/mgcp/mgcp_network.c
index 137aa93..cc1bf44 100644
--- a/openbsc/src/mgcp/mgcp_network.c
+++ b/openbsc/src/mgcp/mgcp_network.c
@@ -109,7 +109,7 @@
 	if (*last_seq == 0)
 		*last_seq = seq;
 	else if (*last_seq + 1 != seq)
-		*lost += abs(*last_seq - seq);
+		*lost = abs(seq - (*last_seq + 1));
 
 	*last_seq = seq;