cron interval help is misleading

[jpeak5]

the admin setting for cron interval has some descriptive text that I think is misleading:
Override (in hours) what a cron interval should be. Hint: zero will force every run.

The problem with this is that this value is used to determined not only when the thing runs, but also which grade items qualify for notification based on the timemodified value, creating a condition where no grade items will be selected, ie timemodified > now() AND timemodified < now()

//block_grade_notify.php:51
        $now = time();

        $runready = ($now - $lastcron) >= ($interval * 60 * 60);

        if (!$runready) {
            return false;
        }



//lib.php:92
$interval = (int)get_config('block_grade_notify', 'croninterval');
        $from = $now - ($interval * 60 * 60);


//lib.php:117
        $sql = "SELECT gg.id, gg.userid, gi.courseid, gi.itemname
                    FROM {grade_items} gi,
                         {grade_grades} gg
                    WHERE gg.userid = :userid
                    AND gi.courseid = :courseid
                    AND gg.itemid = gi.id
                    AND gi.hidden = 0
                    AND gg.hidden = 0
                    AND (gi.itemtype = 'manual' OR gi.itemtype = 'mod')
                    AND (gg.timemodified > :from AND gg.timemodified < :now)";

        $params = array(
            'userid' => $userid,
            'courseid' => $course->id,
            'now' => $now,
            'from' => $from
        );