diff --git a/docs/traffic_shaping.xml b/docs/traffic_shaping.xml
index e89fe62b9..868a3a09c 100644
--- a/docs/traffic_shaping.xml
+++ b/docs/traffic_shaping.xml
@@ -1412,8 +1412,9 @@ eth0          -                1000kbit               hfsc</programlisting>
 
         <listitem>
           <para>For the slope of the first part of the service curve, in
-          theory we can pick any number between 100 and 500 (the parent
-          class's ceiling) with higher numbers providing lower latency.</para>
+          theory we can pick any number between 100 (the rate of class 1:12)
+          and 500 (the rate of the parent class) with higher numbers providing
+          lower latency.</para>
         </listitem>
       </itemizedlist>