diff --git a/src/LedgerConsensus.cpp b/src/LedgerConsensus.cpp
index 855281b010..cb1a55758c 100644
--- a/src/LedgerConsensus.cpp
+++ b/src/LedgerConsensus.cpp
@@ -361,8 +361,10 @@ int LedgerConsensus::statePreClose()
 	bool anyTransactions = theApp->getMasterLedger().getCurrentLedger()->peekTransactionMap()->getHash().isNonZero();
 	int proposersClosed = mPeerPositions.size();
 
+	int sinceClose = theApp->getOPs().getNetworkTimeNC() - mPreviousLedger->getCloseTimeNC();
+
 	if (ContinuousLedgerTiming::shouldClose(anyTransactions, mPreviousProposers, proposersClosed,
-		mPreviousSeconds, mCurrentSeconds))
+		mPreviousSeconds, sinceClose))
 	{ // it is time to close the ledger (swap default and wobble ledgers)
 		Log(lsINFO) << "Closing ledger";
 		mState = lcsESTABLISH;
@@ -428,7 +430,7 @@ void LedgerConsensus::timerEntry()
 		}
 	}
 
-	mCurrentSeconds = theApp->getOPs().getNetworkTimeNC() - mCloseTime;
+	mCurrentSeconds = (mCloseTime != 0) ? (theApp->getOPs().getNetworkTimeNC() - mCloseTime) : 0;
 	mClosePercent = mCurrentSeconds * 100 / mPreviousSeconds;
 
 	switch (mState)
diff --git a/src/LedgerTiming.cpp b/src/LedgerTiming.cpp
index db2bc3031b..122f07f5c6 100644
--- a/src/LedgerTiming.cpp
+++ b/src/LedgerTiming.cpp
@@ -19,6 +19,8 @@ int ContinuousLedgerTiming::shouldClose(
 	int previousSeconds,		// seconds the previous ledger took to reach consensus
 	int currentSeconds)			// seconds since the previous ledger closed
 {
+	assert((previousSeconds > 0) && (previousSeconds < 600));
+	assert((currentSeconds >= 0) && (currentSeconds < 600));
 	Log(lsTRACE) << boost::str(boost::format("CLC::shouldClose Trans=%s, Prop: %d/%d, Secs: %d/%d") %
 		(anyTransactions ? "yes" : "no") % previousProposers % proposersClosed % previousSeconds % currentSeconds);