Passing parameters by reference instead of by value avoids the overhead of making a copy. Passing arguments via copy should only be done when it is
technically mandated, as it is for example with RFC function modules.
Noncompliant code example
PERFORM subr USING a1 a2 a3 a4 a5.
Compliant solution
PERFORM subr CHANGING a1 a2 a3 a4 a5.