How to PHPExcel set auto-columns width

I'm working with PHPExcel to export data for download. When open downloaded files, with cells have big number, it show "#######" instead of value number. I'm tried setAutoSize() for every columns then call $sheet->calculateColumnWidths() but it still not changes. I see calculateColumnWidths() at here, @Mark Baker says "calculateColumnWidths() increase the value by perhaps 5% to try and ensure that the entire column fits". If number length in cell exceed 5%, it seems doen's resolved the problem

UPDATE This is my function to auto size columns:

   function autoFitColumnWidthToContent($sheet, $fromCol, $toCol) {
        if (empty($toCol) ) {//not defined the last column, set it the max one
            $toCol = $sheet->getColumnDimension($sheet->getHighestColumn())->getColumnIndex();
        }
        for($i = $fromCol; $i <= $toCol; $i++) {
            $sheet->getColumnDimension($i)->setAutoSize(true);
        }
        $sheet->calculateColumnWidths();
    }