[CentOS] Problem with procmail

I'm trying to setup email on a new server running CentOS-6.2 (x86_64),
but for some reason email is going to /var/spool/mail/
despite the fact that my .procmailrc starts
-------------------------------
DEFAULT=/var/spool/mail
MAILDIR=/home/tim/Maildir/
SHELL=/bin/sh
DROPPRIVS=yes
-------------------------------
and I have
-------------------------------
MAILER(smtp)dnl
MAILER(procmail)dnl
-------------------------------
in /etc/mail/sendmail.mc .
(I have run /etc/mail/make and restarted sendmail .)

It is as though procmail is not running,
or at least sendmail is not using it.
I have the same setup on my old CentOS-5.7 server,
and this seems to work fine.

Any enlightenment or suggestions gratefully received.


-- 
Timothy Murphy  
e-mail: gayleard /at/ eircom.net
tel: +353-86-2336090, +353-1-2842366
s-mail: School of Mathematics, Trinity College Dublin