Run Priority -- Tomcat running on IBM Midrange boxes

I just happened to discover (while investigating an issue brought up by 
a customer) that the standard catalina.sh shell script in Tomcat 9 has a 
section, conditioned to only execute on IBM Midrange boxes, that sets 
the run priority to 6.

   if $os400; then
     COMMAND='chgjob job('$JOBNAME') runpty(6)'
     system $COMMAND
     # Enable multi threading
     export QIBM_MULTI_THREADED=Y
   fi

When I discussed this on the Midrange Java List, it was pointed out that 
this is an extremely high priority (low RUNPTY values have more priority 
than high RUNPTY values). Terminal session jobs typically have a 
priority of 20; batch jobs typically have a priority of 50, with certain 
high-priority ones getting 35 or 25. Typically, only the most critical 
jobs get 10 or better.

Is there some reason why this is the default for Tomcat?

--
James H. H. Lampert