Output:
======
Test... int(0) 0 0 0 0 9 0
9


Test Code:
======

Test...

<?php

error_reporting(E_ALL);
ini_set("display_errors", 1);

$total = 0;

$january  = new DateTime('2010-01-01 00:00:01');
$february = new DateTime('2010-01-01 00:09:01');
$interval = $february->diff($january);

$year     = $interval->format('%y');
$month    = $interval->format('%m');
$days     = $interval->format('%a');
$hours    = $interval->format('%h');
$minutes  = $interval->format('%i');
$seconds  = (int) $interval->format('%s'); var_dump($seconds); // int(0) $interval->s;

$total   += ($seconds >0 ) ? 1 			   : 0;
$total   += ($minutes >0 ) ? $minutes 		   : 0;
$total   += ($hours   >0 ) ? ($hours * 60) 	   : 0;
$total   += ($days    >0 ) ? (($days * 24) * 60)   : 0;


echo $year . ' ' . $month . ' ' . $days . ' ' . $hours . ' ' . $minutes . ' ' . $seconds . '<br/>';

echo $total;

?>