In the data page for the current charge look for the value tag, then add in this tooltip just after it like this:
<value><?php echo($row_WADWCorders['YVALUE']); ?></value>
<tooltip><![CDATA[#x_label#<br>$#val# ]]></tooltip>
Please give this a try, and let us know if it does not work for you. If you have any further trouble with this it would help us if we had a link to the live chart.