diff --git a/README.md b/README.md
index 1967af0..ef51439 100644
--- a/README.md
+++ b/README.md
@@ -656,10 +656,9 @@ from dateutil.tz import UTC, tzlocal, gettz, resolve_imaginary
 
 ### Arithmetics
 ```python
-<TD>     = <D/DT> - <D/DT>                  # Returns the difference between wall times.
-<D/DT>   = <D/DT> ± <TD>                    # Result can be an imaginary time.
-<TD>     = <TD>   ± <TD>
-<TD>     = <TD>   * <real>
+<D/DT>   = <D/DT> ± <TD>                    # Result can fall into missing hour.
+<TD>     = <D/DT> - <D/DT>                  # Returns the difference, ignoring time jumps.
+<TD>     = <DT_UTC> - <DT_UTC>              # Convert DTs to UTC to get the actual delta.
 ```
 
 
diff --git a/index.html b/index.html
index 1e79e96..0bc80f6 100644
--- a/index.html
+++ b/index.html
@@ -703,10 +703,9 @@ shuffle(&lt;list&gt;)
 <ul>
 <li><strong>When parsing, <code class="python hljs"><span class="hljs-string">'%z'</span></code> also accepts <code class="python hljs"><span class="hljs-string">'±HH:MM'</span></code>.</strong></li>
 </ul>
-<div><h3 id="arithmetics">Arithmetics</h3><pre><code class="python language-python apache hljs">&lt;TD&gt;     = &lt;D/DT&gt; - &lt;D/DT&gt;                  <span class="hljs-comment"># Returns the difference between wall times.</span>
-&lt;D/DT&gt;   = &lt;D/DT&gt; ± &lt;TD&gt;                    <span class="hljs-comment"># Result can be an imaginary time.</span>
-&lt;TD&gt;     = &lt;TD&gt;   ± &lt;TD&gt;
-&lt;TD&gt;     = &lt;TD&gt;   * &lt;real&gt;
+<div><h3 id="arithmetics">Arithmetics</h3><pre><code class="python language-python apache hljs">&lt;D/DT&gt;   = &lt;D/DT&gt; ± &lt;TD&gt;                    <span class="hljs-comment"># Result can fall into missing hour.</span>
+&lt;TD&gt;     = &lt;D/DT&gt; - &lt;D/DT&gt;                  <span class="hljs-comment"># Returns the difference, ignoring time jumps.</span>
+&lt;TD&gt;     = &lt;DT_UTC&gt; - &lt;DT_UTC&gt;              <span class="hljs-comment"># Convert DTs to UTC to get the actual delta.</span>
 </code></pre></div>
 
 <div><h2 id="arguments"><a href="#arguments" name="arguments">#</a>Arguments</h2><div><h3 id="insidefunctioncall">Inside Function Call</h3><pre><code class="python language-python hljs">&lt;function&gt;(&lt;positional_args&gt;)                  <span class="hljs-comment"># f(0, 0)</span>