diff --git a/matrix-util.js b/matrix-util.js
index 40d4773..27ff86b 100644
--- a/matrix-util.js
+++ b/matrix-util.js
@@ -125,12 +125,15 @@ MatrixUtil.prototype.isPartnerOffline = function(partner) {
 
 MatrixUtil.prototype._updateLastResponseTime = function(partner) {
     let matrix = this.matrix;
+    let logger = this.logger;
 
     if (!matrix.buddies[partner]['last_outgoing']) {
+        logger.verbose('No outgoing yet, skip updateLastResponseTime');
         return;
     }
 
     if (!matrix.buddies[partner]['last_outgoing'].last_update_ts) {
+        logger.verbose('No outgoing timestamp yet, skip updateLastResponseTime');
         return;
     }
 
@@ -141,7 +144,8 @@ MatrixUtil.prototype._updateLastResponseTime = function(partner) {
         return;
     }
 
-    matrix.buddies[partner]['last_response_time'] = Math.round((Date.now() - matrix.buddies[partner]['last_outgoing']['last_update_ts'])/1000);
+    let delta = Date.now() - matrix.buddies[partner]['last_outgoing']['last_update_ts'];
+    matrix.buddies[partner]['last_response_time'] = Math.round(delta/1000);
 }
 
 MatrixUtil.prototype._updateLastMessage = function(partner, msg, direction) {