Cron的工作没有更新Magento

I configured Magento on my Centos and added a module with a cron job to execute every 6 hours, however is running every 10 minutes, I installed the Aoe_Scheduler plugin, and Magento folder has the 'centos' user as owner, I had to edit the 'apache' user crontab for the task to be scheduled, but does not run every 6 hours but every 10 minutes.

This is my cron job:

  <crontab>
    <jobs>
      <fatima_syncdb_task>
        <schedule>
          <cron_expr>0 */6 * * *</cron_expr>
        </schedule>
        <run>
          <model>syncdb/syncdb::syncdbcrontask</model>
        </run>
      </fatima_syncdb_task>
    </jobs>
  </crontab>

centos user crontab:

*/5 * * * * /usr/bin/sh /var/www/html/cron.sh

apache user crontab:

*/5 * * * * /usr/bin/sh /var/www/html/cron.sh

I tried to clean Magento cache and restart apache but does not work.

First, please look at you database to table cron_schedule, please verify your cron_job it should be fatima_syncdb_task in the jobs. Check register time and messages of your cron job. Let me know about results.