diff --git a/Shorewall/manpages/shorewall-tcdevices.xml b/Shorewall/manpages/shorewall-tcdevices.xml
index 58229949f..d6b9a8730 100644
--- a/Shorewall/manpages/shorewall-tcdevices.xml
+++ b/Shorewall/manpages/shorewall-tcdevices.xml
@@ -160,7 +160,9 @@
           how often the rate is estimated and how many samples are retained
           for estimating. Please see <ulink
           url="http://ace-host.stuart.id.au/russell/files/tc/doc/estimators.txt">http://ace-host.stuart.id.au/russell/files/tc/doc/estimators.txt</ulink>
-          for details.</para>
+          for details. If not specified, the default
+          <replaceable>interval</replaceable> is 250ms and the default
+          <replaceable>decay_interval</replaceable> is 4sec.</para>
         </listitem>
       </varlistentry>
 
diff --git a/Shorewall/manpages/shorewall-tcinterfaces.xml b/Shorewall/manpages/shorewall-tcinterfaces.xml
index 73d87f07d..43423ce17 100644
--- a/Shorewall/manpages/shorewall-tcinterfaces.xml
+++ b/Shorewall/manpages/shorewall-tcinterfaces.xml
@@ -172,7 +172,9 @@
           how often the rate is estimated and how many samples are retained
           for estimating. Please see <ulink
           url="http://ace-host.stuart.id.au/russell/files/tc/doc/estimators.txt">http://ace-host.stuart.id.au/russell/files/tc/doc/estimators.txt</ulink>
-          for details.</para>
+          for details. If not specified, the default
+          <replaceable>interval</replaceable> is 250ms and the default
+          <replaceable>decay_interval</replaceable> is 4sec.</para>
         </listitem>
       </varlistentry>