I did that but the last column is still wider than the rest.
$html .= "<table class='tbl-summary' style='font-size:12px'>";
$html .= "<thead>
<th width='500'></th>
<th width='250'>FY 1</th>
<th width='250'>FY 2</th>
<th width='250'>FY 3</th>
<th width='250'>FY 4</th>
<th width='250'>FY 5</th>
</thead>
";
Im using phpdocx-corporate-5.5