hi i got the same problem.. add 0.71 to excel cell width value and give that value to the
$objPHPExcel->getActiveSheet()->getColumnDimension('A')->setWidth(10);
eg: A Column width = 3.71 (excel value)
give column width = 4.42
will give the output file with same cell width.
$objPHPExcel->getActiveSheet()->getColumnDimension('A')->setWidth(4.42);
hope this help