Output several timestamps in ant

The Ant buildfile snippet below is an attempt to simply output the time before and after each sql script is run. I cannot change the structure of the Ant targets (create-tables must call run-sql-script just as it does). The problem is that the properties (time and time2) are immutable (http://ant.apache.org/manual/Tasks/property.html) and thus only time the first operation and not the second. Is there no way to do what I'm trying to do in Ant?

  <target name="create-tables">
    <antcall target="run-sql-script">
      <param name="db.script" value="teams.sql"/>
    </antcall>

    <!-- Create the base UDM schema. -->
    <antcall target="run-sql-script">
      <param name="db.script" value="players.sql"/>
    </antcall>
  </target>
  <target name="run-sql-script">
    <tstamp>
      <format property="time" pattern="MM/dd/yyyy hh:mm:ss aa"
          offset="-5" unit="hour"/>
    </tstamp>
    <echo>before: ${time}</echo>
    <sql
        classpath="${classpath}"
        driver="${db.driver}"
        url="${db.url}"
        userid="${db.userid}"
        password="${db.password}"
        src="${script.dir}/${db.script}"
        delimiter="${script.delimiter}"
        onerror="abort">
    </sql>              
    <tstamp>
      <format property="time2" pattern="MM/dd/yyyy hh:mm:ss aa"
            offset="-5" unit="hour"/>
    </tstamp>
    <echo>after: ${time2}</echo>
  </target>