PROC SUMMARY/MEANS will produce incorrect results when one or more CLASS
variables are formatted to the HEX format with a width less than 16.

This occurs with the default SAS system option or if the PROC statement
option is set to THREADS. In order to circumvent this problem, set the
SAS system option or PROC statement option to NOTHREADS.

   OPTIONS NOTHREADS;

or

   PROC SUMMARY DATA=DSN NOTHREADS;



A SAS 9.0 update for this issue is available for OS/390.  Download and
install the "Threaded HEXw. Format Update" located at:

http://ftp.sas.com/techsup/download/hotfix/90_updates.html#010527

Operating System and Release Information