On CentOS (my version is 6.5) when editing crontab you must close the editor to reflect your changes in CRON.
crontab -e
After that command You can see that new entry appears in /var/log/cron
Sep 24 10:44:26 ***** crontab[17216]: (*****) BEGIN EDIT (*****)
But only saving crontab editor after making some changes does not work. You must leave the editor to reflect changes in cron. After exiting new entry appears in the log:
Sep 24 10:47:58 ***** crontab[17216]: (*****) END EDIT (*****)
From this point changes you made are visible to CRON.