*INLR = *on files and resources are released
Return ends the program returning to calling program.
Return without *INLR = *On resources remain locked until job ends or this program is recalled and changes the value of *INLR.
WoodEngineer’s correct – saves resources to leave *INLR off, keep in mind that initialization and *INZSR do not run on subsequent calls.
Another important difference is that setting on LR ends the called program when the cycle ends, but using RETURN returns control to the calling program immediately. Therefore after LR is on, you can still continue processing additional commands.