my sudo commands work and I think it's great but I'm having a problem getting the command aliases to work.

below is my visudo...

#Host alias specification
#User alias specification
#Cmnd alias specification
Cmnd_Alias OFF = /sbin/poweroff
Cmnd_Alias DIAL = /usr/sbin/ppp-go
Cmnd_Alias HANG = /usr/sbin/ppp-off
#Defaults specification
#User privilege specification
root = ALL=(ALL) ALL
brandonweinberg = ALL= OFF, DIAL, HANG

example of my problem
when I type sudo /sbin/poweroff it works
when I type sudo OFF the command is not found