ok, check your spamfilter users list. ( spamfilter->user/domain) and be sure that the mailboxes/domains are using the policy you want.
Yes, with the quarantine cutoff you can set at what level the email is forwarded to the quarantine admin. 0 = Notification off
The score 5.0? Sure, it must be a score of one policy. Default's scores are in the database and in the 50-user file (but this file is patched for ispconfig's install/update, and scores are pretty high)