cron_flags in jails rc.conf

[Fbsd8]

I found this statement in the rc.conf file of a jail.
cron_flags="$cron_flags -J 15"

I checked the cron manpage and found info on this.

The -J 15 is the range cron is to sleep before launching the cron jobs 
for the superuser.  The -j option does the same thing for non-superuser 
jobs.

Looking at the system's /etc/crontab file are those superuser jobs?

Also is the above rc.conf statement coded correctly?