<?php
require_once('/usr/share/moodle/config.php');
require_once('/usr/share/moodle/lib/gradelib.php');
$courses=get_records('course');
foreach ($courses as $course){
if(grade_regrade_final_grades($course->id))echo "updated grades for $course->shortname<br>";
}
?>
I've managed to recalculate all the grades- wrote a little script: