If the configuration has a rate of 0.000, Audio Banking will not read any message for that rate, even if one was originally recorded.  For example, say you have requested a message to be recorded for item #9 on the configuration, but then you forget to go in and actually enter the rate into your configuration, or you accidentally delete the rate later.  That recording will never be read to the member.  Once you go in and enter a rate in position 9, then message #9 will be read along with that rate.