A lot of SPAM and Infected emails not being filtered

Hello,

We have Mail Security for Exchane deployed and it is reporting that it's picking up some SPAM and infected emails, but I've noticed a lot still make it through.  I currenlty have the following settings:

Antivirus Settings

1. Enabled virus scanning (enabled)
2. Bloodhound detention (off)
3. Delete Mass-mailer worm-infected message (enabled)
4. Advanced heuristics detention (enabled)
5. Basic Virus Rule (Always enabled)
6. Unrepairable Virus Rule (Always enabled)
7. Security Risk Rule (Enabled)

Premium AntiSpam Settings

1. Enable Symantec Premium AntiSpam (Enabled)
2. Open Proxy list (enabled)
3. Safe List (enabled
4. FastPass (enabled
5. Flag messages as suspected spam (enabled with score of 72)

Premium AntiSpam Actions

1. If message is SPAM (Reject)
2. If suspected SPAM (Allow) - I just changed this to amend the subject to warn that it might be spam

Just wondering if anyone can comment or make recommendations on how to MSE might be able to function better?  i.e. what score are other people using, etc.

Thanks.