The second number is the priority. I'm afraid I don't know what the last entry is is for. Besides reading the service skeleton file ( probably /etc/init.d/skeleton ) and "man chkconfig" you may also want to read the man page for the insserv command. It does more in explaining the contents of the commented headers.
This is a fragment of my /etc/init.d/hplip file:
# For chkconfig the HPLIP priority (ie: 50) must be less the cupsd
# priority (ie: 55).
# For LSB install_initd the cups script file should have "hplip" in the
# Should-Start field.
# chkconfig: 2345 50 10
# description: Start/stop script for HP Linux Imaging and Printing (HPLIP).
Also, you might consider having the script in /etc/init.d stay very close to the model skeleton script, or one of the other scripts that you use as a model. Instead of this script doing the work, have it start, stop, restart, the actual script. There's nothing wrong with using the same start() and stop() functions as one of the other services. The hplip script simply starts the hpiod program. Changing the names of variables so they make more sense and the name of the target program to the name of your script, you could use this or another init.d script almost as is. This would also decouple your script from the init process.
When I grep'ed for "chkconfig" in the init.d scripts, I noticed that most didn't have the chkconfig <runlevels> <priority> <lastentry> line but they all had the instserv header information.