typical spam header

[bbarrons]

Here is a typical header from one of our junk folders. Spam gets scored at 27. I have at this point my kill% set to 24 and my tag set at 15. I have been lowering it every few days, restarting zimbra and then watching. I have no false positives at all, spam is getting marked as it should but with a score of 27 shouldnt it be killed rather than delivered? I would prefer to have this email just not be delivered. This is on a 5.0.18 system.

X-Spam-Flag: YES
X-Spam-Score: 27.77
X-Spam-Level: ***************************
X-Spam-Status: Yes, score=27.77 tagged_above=-10 required=3
tests=[BAYES_99=9.5, HTML_MESSAGE=0.001, LOCAL_RULE_APNIC_6=4.123,
MIME_HTML_ONLY=1.457, RAZOR2_CF_RANGE_51_100=0.5,
RAZOR2_CF_RANGE_E8_51_100=1.5, RAZOR2_CHECK=0.5,
RCVD_IN_BL_SPAMCOP_NET=1.96, URIBL_AB_SURBL=1.86, URIBL_BLACK=3,
URIBL_JP_SURBL=1.501, URIBL_WS_SURBL=1.5, URI_HEX=0.368]
thanks for any help that can be provided.
Bill

[bbarrons]

no one have a reply that can help with this?
Bill