[exim] condition problem

Hi Everybody ,

            My spam check condition like below , but I saw that more then
300K files are passing and checked from spamassassin. I'm controling spamd
log ! 

Wed Feb 8 13:57:26 2006 [2418] info: spamd: clean message (1.8/7.0) for
nobody:0 in 1.2 seconds, 890167 bytes.
Wed Feb 8 13:57:20 2006 [2476] info: spamd: clean message (6.0/7.0) for
nobody:0 in 113.6 seconds, 1184550 bytes.
Wed Feb 8 13:57:16 2006 [2432] info: spamd: clean message (1.2/7.0) for
nobody:0 in 1.0 seconds, 1336499 bytes.
Wed Feb 8 13:44:50 2006 [2425] info: spamd: clean message (4.4/7.0) for
nobody:0 in 27.5 seconds, 647758 bytes.

   warn    spam      = nobody:true
           condition = ${if < {$message_size}{300K}}
           message   = X-Spam_score: $spam_score\n\
                       X-Spam_score_int: $spam_score_int\n\
                       X-Spam_bar: $spam_bar\n\
                       X-Spam_report: $spam_report

Do Somebody have same problem like me ?
Vahric