OT? Spamassassin's auto-whitelisting and MailScanner

[webmaster]

I've been watching some of the spam I've been recieving as of late and
noticing that some spam with a score above the mark I've set has been
getting into the mailbox declared as non-spam (auto whitelisted). Here is
a sample header:

X-sapl.ab.ca-MailScanner-SpamCheck: not spam (whitelisted),
        SpamAssassin (score=22.391, required 9, AS_SEEN_ON 1.49,
        BANG_GUARANTEE 1.00, BAYES_99 5.40, DATE_IN_PAST_96_XX 1.53,
        DNS_FROM_RFCI_DSN 0.29, HTML_MESSAGE 0.10, INCREASE_SEX 1.73,
        LOSEBODYFAT 2.88, MIME_HTML_NO_CHARSET 0.56, MIME_HTML_ONLY 0.32,
        RAVAGESOFAGING 1.98, REVERSE_AGING 1.00, WRINKLES 4.10)

Until just recently I had:

SpamAssassin Auto Whitelist = yes

in my MailScanner.conf set. I just changed this to 'no' 5 minutes ago I
changed this and reset SIGHUP'd all my MailScanner Processes on the mail
server. Am I right in thinking that by setting this option in
MailScanner.conf *should* be able to take high-scoring spam (and in my
case, as set in my high scoring spam options, delete) the spam and not
pass it along to the mailbox? Is there a way in SpamAssassin to
automatically blacklist highscoring spam?

I'm a MailScanner/SpamAssassin novice so any suggestions are greatly
appriciated. I'm currently running MailScanner version 4.23-11 and
SpamAssassin 2.61.

Thanks In Advance,
Peter Verhagen
St. Albert Public Library