RHEL sudo still not allowed for user 'tina'

I'd like 2 users, 'tina' and 'lu' to execute a few utils like /bin/chmod. Here's the relevant portion of my /etc/sudoers file.

tina,lu ALL=/bin/chmod /bin/chown /bin/chgrp

Then I logged in as myself, and then logged in as tina using

su - tina 

Then I tried to get the tina username to do chmod on a file. tina's permissions don't seem to be working. Here's the output of sudo -l -U tina

Matching Defaults entries for tina on this host:
    requiretty, !visiblepw, env_reset, env_keep="COLORS DISPLAY HOSTNAME HISTSIZE INPUTRC
    KDEDIR LS_COLORS MAIL PS1 PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE LC_COLLATE
    LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER
    LC_TELEPHONE LC_TIME LC_ALL LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY"

Runas and Command-specific defaults for tina:


User tina may run the following commands on this host:
    (root) /bin/chmod /bin/chown /bin/chgrp

And when I actually try to do a chmod logged in as her. copyf is a new shell script I'm working on.

tina 118->chmod 770 copyf
chmod: changing permissions of `copyf': Operation not permitted
tina 119->sudo chmod 770 copyf
Sorry, user tina is not allowed to execute '/bin/chmod 770 copyf' as root on xpp.

Did I forget to set something up?