diff --git a/osscan2.cc b/osscan2.cc
index 261af04e9..1d32061b9 100644
--- a/osscan2.cc
+++ b/osscan2.cc
@@ -534,7 +534,7 @@ static void doSeqTests(OsScanInfo *OSI, HostOsScan *HOS) {
 
       for (hostI = OSI->incompleteHosts.begin(); hostI != OSI->incompleteHosts.end(); hostI++) {
         if (HOS->nextTimeout((*hostI)->hss, &tmptv)) {
-          if (TIMEVAL_SUBTRACT(tmptv, stime) < 0)
+          if (TIMEVAL_BEFORE(tmptv, stime))
             stime = tmptv;
         }
       }
@@ -548,7 +548,7 @@ static void doSeqTests(OsScanInfo *OSI, HostOsScan *HOS) {
           break;
         }
 
-        if (!foundgood || TIMEVAL_SUBTRACT(tmptv, stime) < 0) {
+        if (!foundgood || TIMEVAL_BEFORE(tmptv, stime)) {
           stime = tmptv;
           foundgood = true;
         }
@@ -567,7 +567,7 @@ static void doSeqTests(OsScanInfo *OSI, HostOsScan *HOS) {
 
       gettimeofday(&now, NULL);
 
-      if (!ip && TIMEVAL_SUBTRACT(stime, now) < 0) {
+      if (!ip && TIMEVAL_BEFORE(stime, now)) {
         timedout = true;
         break;
       } else if (!ip) {
@@ -705,7 +705,7 @@ static void doTUITests(OsScanInfo *OSI, HostOsScan *HOS) {
       for (hostI = OSI->incompleteHosts.begin(); hostI != OSI->incompleteHosts.end();
           hostI++) {
         if (HOS->nextTimeout((*hostI)->hss, &tmptv)) {
-          if (TIMEVAL_SUBTRACT(tmptv, stime) < 0)
+          if (TIMEVAL_BEFORE(tmptv, stime))
             stime = tmptv;
         }
       }
@@ -720,7 +720,7 @@ static void doTUITests(OsScanInfo *OSI, HostOsScan *HOS) {
           break;
         }
 
-        if (!foundgood || TIMEVAL_SUBTRACT(tmptv, stime) < 0) {
+        if (!foundgood || TIMEVAL_BEFORE(tmptv, stime)) {
           stime = tmptv;
           foundgood = true;
         }
@@ -738,7 +738,7 @@ static void doTUITests(OsScanInfo *OSI, HostOsScan *HOS) {
 
       gettimeofday(&now, NULL);
 
-      if (!ip && TIMEVAL_SUBTRACT(stime, now) < 0) {
+      if (!ip && TIMEVAL_BEFORE(stime, now)) {
         timedout = true;
         break;
       } else if (!ip) {
@@ -1277,7 +1277,7 @@ bool HostOsScan::nextTimeout(HostOsScanStats *hss, struct timeval *when) const {
 
   for (probeI = hss->probesActive.begin(); probeI != hss->probesActive.end(); probeI++) {
     TIMEVAL_ADD(probe_to, (*probeI)->sent, timeProbeTimeout(hss));
-    if (firstgood || TIMEVAL_SUBTRACT(probe_to, earliest_to) < 0) {
+    if (firstgood || TIMEVAL_BEFORE(probe_to, earliest_to)) {
       earliest_to = probe_to;
       firstgood = false;
     }
@@ -1580,7 +1580,7 @@ bool HostOsScan::hostSendOK(HostOsScanStats *hss, struct timeval *when) const {
   /* Any timeouts coming up? */
   for (probeI = hss->probesActive.begin(); probeI != hss->probesActive.end(); probeI++) {
     TIMEVAL_MSEC_ADD(probe_to, (*probeI)->sent, timeProbeTimeout(hss) / 1000);
-    if (TIMEVAL_SUBTRACT(probe_to, earliest_to) < 0) {
+    if (TIMEVAL_BEFORE(probe_to, earliest_to)) {
       earliest_to = probe_to;
     }
   }
@@ -1588,7 +1588,7 @@ bool HostOsScan::hostSendOK(HostOsScanStats *hss, struct timeval *when) const {
   // Will any scan delay affect this?
   if (hss->sendDelayMs > 0) {
     TIMEVAL_MSEC_ADD(sendTime, hss->lastProbeSent, hss->sendDelayMs);
-    if (TIMEVAL_MSEC_SUBTRACT(sendTime, now) < 0)
+    if (TIMEVAL_BEFORE(sendTime, now))
       sendTime = now;
     tdiff = TIMEVAL_MSEC_SUBTRACT(earliest_to, sendTime);
 
@@ -1653,13 +1653,13 @@ bool HostOsScan::hostSeqSendOK(HostOsScanStats *hss, struct timeval *when) const
   /* Any timeouts coming up? */
   for (probeI = hss->probesActive.begin(); probeI != hss->probesActive.end(); probeI++) {
     TIMEVAL_MSEC_ADD(probe_to, (*probeI)->sent, timeProbeTimeout(hss) / 1000);
-    if (TIMEVAL_SUBTRACT(probe_to, earliest_to) < 0) {
+    if (TIMEVAL_BEFORE(probe_to, earliest_to)) {
       earliest_to = probe_to;
     }
   }
 
   TIMEVAL_ADD(sendTime, hss->lastProbeSent, maxWait);
-  if (TIMEVAL_SUBTRACT(sendTime, now) < 0)
+  if (TIMEVAL_BEFORE(sendTime, now))
     sendTime = now;
   tdiff = TIMEVAL_SUBTRACT(earliest_to, sendTime);
 
diff --git a/scan_engine.cc b/scan_engine.cc
index fa15c0b26..ca3249b3a 100644
--- a/scan_engine.cc
+++ b/scan_engine.cc
@@ -307,7 +307,7 @@ void GroupScanStats::probeSent(unsigned int nbytes) {
      connection is capable of the maximum. */
 
   if (o.min_packet_send_rate != 0.0) {
-      if (TIMEVAL_SUBTRACT(send_no_later_than, USI->now) > 0) {
+      if (TIMEVAL_AFTER(send_no_later_than, USI->now)) {
         /* The next scheduled send is in the future. That means there's slack time
            during which the sending rate could drop. Pull the time back to the
            present to prevent that. */
@@ -346,7 +346,7 @@ bool GroupScanStats::sendOK(struct timeval *when) const {
      return false. If not, mark now as a good time to send and allow the
      congestion control to override it. */
   if (o.max_packet_send_rate != 0.0) {
-    if (TIMEVAL_SUBTRACT(send_no_earlier_than, USI->now) > 0) {
+    if (TIMEVAL_AFTER(send_no_earlier_than, USI->now)) {
       if (when)
         *when = send_no_earlier_than;
       return false;
@@ -361,7 +361,7 @@ bool GroupScanStats::sendOK(struct timeval *when) const {
      control. If we're behind schedule, return true to indicate that we need to
      send right now. */
   if (o.min_packet_send_rate != 0.0) {
-    if (TIMEVAL_SUBTRACT(send_no_later_than, USI->now) > 0) {
+    if (TIMEVAL_AFTER(send_no_later_than, USI->now)) {
       if (when)
         *when = send_no_later_than;
     } else {
@@ -548,7 +548,7 @@ bool HostScanStats::sendOK(struct timeval *when) const {
   /* If the group stats say we need to send a probe to enforce a minimum
      scanning rate, then we need to step up and send a probe. */
   if (o.min_packet_send_rate != 0.0) {
-    if (TIMEVAL_SUBTRACT(USI->gstats->send_no_later_than, USI->now) <= 0) {
+    if (!TIMEVAL_AFTER(USI->gstats->send_no_later_than, USI->now)) {
       if (when)
         *when = USI->now;
       return true;
@@ -594,7 +594,7 @@ bool HostScanStats::sendOK(struct timeval *when) const {
        probeI++) {
     if (!(*probeI)->timedout) {
       TIMEVAL_MSEC_ADD(probe_to, (*probeI)->sent, probeTimeout() / 1000);
-      if (TIMEVAL_SUBTRACT(probe_to, earliest_to) < 0) {
+      if (TIMEVAL_BEFORE(probe_to, earliest_to)) {
         earliest_to = probe_to;
       }
     }
@@ -1049,7 +1049,7 @@ bool UltraScanInfo::sendOK(struct timeval *when) const {
       for (host = incompleteHosts.begin(); host != incompleteHosts.end();
            host++) {
         if ((*host)->nextTimeout(&tmptv)) {
-          if (TIMEVAL_SUBTRACT(tmptv, lowhtime) < 0)
+          if (TIMEVAL_BEFORE(tmptv, lowhtime))
             lowhtime = tmptv;
         }
       }
@@ -1064,7 +1064,7 @@ bool UltraScanInfo::sendOK(struct timeval *when) const {
         break;
       }
 
-      if (!foundgood || TIMEVAL_SUBTRACT(lowhtime, tmptv) > 0) {
+      if (!foundgood || TIMEVAL_AFTER(lowhtime, tmptv)) {
         lowhtime = tmptv;
         foundgood = true;
       }
@@ -1076,11 +1076,11 @@ bool UltraScanInfo::sendOK(struct timeval *when) const {
   /* Defer to the group stats if they need a shorter delay to enforce a minimum
      packet sending rate. */
   if (o.min_packet_send_rate != 0.0) {
-    if (TIMEVAL_MSEC_SUBTRACT(gstats->send_no_later_than, lowhtime) < 0)
+    if (TIMEVAL_BEFORE(gstats->send_no_later_than, lowhtime))
       lowhtime = gstats->send_no_later_than;
   }
 
-  if (TIMEVAL_MSEC_SUBTRACT(lowhtime, now) < 0)
+  if (TIMEVAL_BEFORE(lowhtime, now))
     lowhtime = now;
 
   if (when)
diff --git a/scan_engine_raw.cc b/scan_engine_raw.cc
index b8af542ab..964145804 100644
--- a/scan_engine_raw.cc
+++ b/scan_engine_raw.cc
@@ -415,7 +415,7 @@ int get_ping_pcap_result(UltraScanInfo *USI, struct timeval *stime) {
                                        &linkhdr, true);
     gettimeofday(&USI->now, NULL);
     if (!ip_tmp) {
-      if (TIMEVAL_SUBTRACT(*stime, USI->now) < 0) {
+      if (TIMEVAL_BEFORE(*stime, USI->now)) {
         timedout = true;
         break;
       } else {
@@ -1433,7 +1433,7 @@ bool get_arp_result(UltraScanInfo *USI, struct timeval *stime) {
     if (rc == -1)
       fatal("Received -1 response from read_arp_reply_pcap");
     if (rc == 0) {
-      if (TIMEVAL_SUBTRACT(*stime, USI->now) < 0) {
+      if (TIMEVAL_BEFORE(*stime, USI->now)) {
         timedout = true;
         break;
       } else {
@@ -1512,7 +1512,7 @@ bool get_ns_result(UltraScanInfo *USI, struct timeval *stime) {
     if (rc == -1)
       fatal("Received -1 response from read_arp_reply_pcap");
     if (rc == 0) {
-      if (TIMEVAL_SUBTRACT(*stime, USI->now) < 0) {
+      if (TIMEVAL_BEFORE(*stime, USI->now)) {
         timedout = true;
         break;
       } else {
@@ -1610,7 +1610,7 @@ bool get_pcap_result(UltraScanInfo *USI, struct timeval *stime) {
       to_usec = 2000;
     ip_tmp = (struct ip *) readip_pcap(USI->pd, &bytes, to_usec, &rcvdtime, &linkhdr, true);
     gettimeofday(&USI->now, NULL);
-    if (!ip_tmp && TIMEVAL_SUBTRACT(*stime, USI->now) < 0) {
+    if (!ip_tmp && TIMEVAL_BEFORE(*stime, USI->now)) {
       timedout = true;
       break;
     } else if (!ip_tmp)