sar problem

From: Kenneth (kenneth_at_cde.com)
Date: 07/30/03 

Date: Wed, 30 Jul 2003 21:32:35 +0800

In AIX 4.3.3 ML10, I capture the sar by
sar -A -o sar.dat from 23:00 - 10:00 (next day)
However I can review the statistic from 23:00 - 23:30 by
$ sar -A -f sar.dat -s 23:00 -e 23:30 but if I want to check the statistic
between 09:00 - 09:30, it has no report. But I can get all the data by
sar -A -f sar.dat without specify any time.

Any advise?