antisplog missing a lot of spam

When I first used antisplog it worked really well. I had to stop using it when an update caused it to spam my own site but with recent updates I've got it install. However, I find that it's letting lots of spam through. Sites with adult content and gambling and others aren't being flagged. I have splog certainty set to 80% and posting blog at 78%. Is there something else I can try. More spam sites are being allowed than are being spammed (only about 25% of the spam is being flagged).