procmail not bouncing email if over quota

I have just installed procmail 3.10 on a DecSystem running Ultrix 4.5.
I have done some testing and it will deliver email to the spool
 (/var/spool/mail/username/username).
I have recently enabled quotas on /var/spool/mail (but have not 
assigned quotas to my users as of yet).  I would like procmail to
bounce the email message back to the sender if the user is over 
quota on /var/spool/mail.  For testing, I gave the test account a quota
of 1000 and its mbox is 1800. 
/var/spool/mail    1831*   1000    1100       2      11       0       0)
The email was delivered anyway.

I have created sendmail.cf-procmail file with procmail as the local
delivery agent:
Mlocal, P=/usr/local/bin/procmail, F=lsSDFMhPfn, S=10/30, R=20/40,
        A=procmail -a $h -d $u

I used this command to send the test email to the over quota account.
#/usr/lib/sendmail -C/etc/sendmail.cf-procmail ellen < /tmp/email


Do I need to turn something on in procmail and recompile?  Is sendmail the
culprit?  Or is my testing flawed? Please send any suggestions to
Ellen(_dot_)Davis(_at_)uc(_dot_)edu or to the list.




 Ellen Davis