[Exim] Default retry rate exceeds limit in RFC1123

Ian Jackson has pointed me at RFC1123, section 5.3.1.1 Sending Strategy

            The sender MUST delay retrying a particular destination
            after one attempt has failed.  In general, the retry
            interval SHOULD be at least 30 minutes; however, more
            sophisticated and variable strategies will be beneficial
            when the sender-SMTP can determine the reason for non-
            delivery.

The default retry rule in src/configure.default (exim 4.12) is
*                      *           F,2h,15m; G,16h,1h,1.5; F,4d,6h

which for the first 2 hours retries twice as often as the
SHOULD requests. Are there good reasons for the default config
to ignore the advice of an RFC ?

--
Dr. Andrew C. Aitchison        Computer Officer, DPMMS, Cambridge
A.C.Aitchison@???    http://www.dpmms.cam.ac.uk/~werdna