SpamAssassin weightings - am I missing something?

[Jonathan Matthews <jaycee.removeifnotspam@jaycee.uklinux.net>]

Quick Spamassassin question:

I've got SpamAssassin 2.43 installed, and it's working well.

However, I noticed the two lines quoted below in the altered body of 
some spam that it caught recently:

SPAM: EXCUSE_16          (-0.3 points) BODY: I wonder how many emails they sent in error...
SPAM: EXCUSE_14          (-0.2 points) BODY: Tells you how to stop further spam

It seems strange to me that these two reasons should /decrease/ the 
probability of the email being spam.

I know that the weightings attached to different rules are 
user-definable, so I'm not asking "how do I stop this behaviour" - I can 
easily go and redefine the weights.

I'd just like to get some confirmation that these weightings are wrong.  
It's the stock install of SpamAssassin in testing, with no alterations 
made to the config at all.  Should I file a bug, change my own 
weightings or go away in shame, having made a fool of myself publicly?

Cheers!
-- jc