Spam score - a sum of all listed tests or not?

Hello,


a quick question - I recently updated my mail server and therefore, I
was paying a bit more attention to spam filtering. I noticed that total
score, indicated in X-Spam-Status header, does not equal the sum of all
the tests listed.

Here I have a real-world example - this is the X-Spam-Satusheader of a
received spam message (I added newlines for clarity):

X-Spam-Status: No, score=-0.499 tagged_above=-999 required=4 tests=[
DKIMWL_WL_MED=-0.001,
DKIM_SIGNED=0.1,
DKIM_VALID=-0.1,
DKIM_VALID_AU=-0.1,
HTML_MESSAGE=0.001,
MAILING_LIST_MULTI=-1,
RCVD_IN_MSPIKE_H4=-0.01,
RCVD_IN_MSPIKE_WL=-0.01,
SPF_HELO_NONE=0.001,
SPF_PASS=-0.001,
T_KAM_HTML_FONT_INVALID=0.01,
RCVD_TLS_ALL=0,
RWL_MAILSPIKE_VERYGOOD=0,
HAS_LIST_UNSUB=-0.01,
R_DKIM_ALLOW=0,
URIBL_GREY=1.5,
MANY_INVISIBLE_PARTS=0.3,
DMARC_POLICY_ALLOW=0,
BAD_REP_POLICIES=0.1,
REPLYTO_DOM_NEQ_FROM_DOM=0,
PREVIOUSLY_DELIVERED=0,
PRECEDENCE_BULK=0,
DKIM_TRACE=0,
MIME_TRACE=0,
MIME_BASE64_TEXT=0.1,
HAS_REPLYTO=0,
RCVD_COUNT_ONE=0,
ASN=0,
MIME_GOOD=-0.1,
TO_DN_EQ_ADDR_ALL=0,
R_SPF_ALLOW=0,
FREEMAIL_REPLYTO=0,
FORGED_SENDER=0.3,
TO_MATCH_ENVRCPT_ALL=0,
ONCE_RECEIVED=0.1,
ARC_NA=0,
RCPT_COUNT_ONE=0,
FROM_NEQ_ENVFROM=0,
FROM_HAS_DN=0
] |autolearn=ham autolearn_force=no|

||

So - total score is -0.499, but if I manually sum up all the tests, it
comes out to 1.18.

Is this something that normally occurs in Amavis or is this a distro
(CentOS 7) specific problem?


   Best regards,

  Danilo