Query plan missing ParameterCompiledValue
The XML plan uploaded includes:

&lt;ParameterList&gt;
    &lt;ColumnReference Column="@today" ParameterCompiledValue="'2016-03-04 00:00:00.000'" /&gt;
&lt;/ParameterList&gt;


There are multiple statements in the batch, so the XML contains multiple &lt;StmtSimple&gt; elements under &lt;Statements&gt;. Aside from the final select, the other statements are all assignments, which are not queries, so there is no parameter list at that level.

As Kin mentioned, you may find it useful to look at the plans in SQL Sentry Plan Explorer:



Related question:

Parameter Sniffing vs VARIABLES vs Recompile vs OPTIMIZE FOR UNKNOWN