SpamAssassin to blacklist and unblacklist

SpamAssassin has a feature to blacklist and unblacklist certain e-mailaddressen. But recently I noticed something interesting that may need some more investigation. I have all addresses for domain example.org blacklisted, but also unblacklisted certain functional addresses as is shown in the example below.

blacklist_from          *@example.org
unblacklist_from        abuse@*
unblacklist_from        hostmaster@*
unblacklist_from        postmaster@*
unblacklist_from        security@*
unblacklist_from        webmaster@*

Now I expected that webmaster@example.org was going to be unblacklisted, meaning the mail would have both a spamscore of both +100 and -100 making it effective 0 again. This modification resulted in a spamscore of +100 and makes me worry that unblacklisting will demand that the domain part needs to be specified instead of having a wildcard. This will require some more testing in the near future, but for now it may affect other installations.