diff --git a/src/internet/model/tcp-rate-ops.cc b/src/internet/model/tcp-rate-ops.cc
index e814ddcd8..afe131a8e 100644
--- a/src/internet/model/tcp-rate-ops.cc
+++ b/src/internet/model/tcp-rate-ops.cc
@@ -178,11 +178,11 @@ TcpRateLinux::SkbDelivered (TcpTxItem * skb)
   if (m_rateSample.m_priorDelivered == 0
       || skbInfo.m_delivered > m_rateSample.m_priorDelivered)
     {
+      m_rateSample.m_ackElapsed       = Simulator::Now () - m_rateSample.m_priorTime;
       m_rateSample.m_priorDelivered   = skbInfo.m_delivered;
       m_rateSample.m_priorTime        = skbInfo.m_deliveredTime;
       m_rateSample.m_isAppLimited     = skbInfo.m_isAppLimited;
       m_rateSample.m_sendElapsed      = skb->GetLastSent () - skbInfo.m_firstSent;
-      m_rateSample.m_ackElapsed       = Simulator::Now () - skbInfo.m_deliveredTime;
 
       m_rateSampleTrace (m_rateSample);