ksh errors out in SQL database with 'exit 45'

Issue

The exit code from sqlplus is echoed to &4 and then using 4>&1 so that the STATUS variable ends up being assigned the exit code from sqlplus. It is then sanity-checked to make sure that it has a value (hopefully 0). If it doesn't have a value the script will exit with 45. Below is noticed errors:

SQL> SET ECHO OFF;
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters and Automatic Storage Management options
+ echo 0
+ 1>& 4
+ STATUS=''
+ [ 0 -ne 0 ]
+ [ -z '' ]
+ exit 45

STATUS=`( (print ${database_password} | ${database_home}/bin/sqlplus "${database_username}"@"${database_connection_string}" @"fubar.sql" 4>&- 2>&1; echo $? >&4) | tee execute_61884_790746_5331464_Update_Tax_income_table_for_2013.log 1>&2 4>&-) 4>&1`
if [ "$?" -ne 0 ]
 then
   exit 44
fi
if [ -z "$STATUS" ]
then
  exit 45
fi
exit $STATUS

This works fine in ksh88 as well as in ksh93u and ksh93u+. Here is the correct output from ksh93u:

SQL> SET ECHO OFF;
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application Clusters and Automatic Storage Management options
+ echo 0
+ 1>& 4
+ STATUS=0
+ [ 0 -ne 0 ]
+ [ -z 0 ]
+ exit 0