I'd go with the AVRs leveling functionality, myself. Auto-leveling on the Roku switches to 2-channel stereo, right?
Why use auto leveling at all? It doesn't make sense to use it if you've gone to the expense and trouble of buying a nice AVR system. Using the function will kill whatever dynamic range you have. Dynamic range is the difference between the softest sounds and the loudest. You want that to make ti lifelike and a true surround system. Making something loud as low as something soft just makes no sense. Using it on a tv only system is one thing but not in a AVR system if you want true surround and movie quality sound like I do.
Roku 2100x, (2) Roku2 3100x ,Roku 2720X .FIOS Quantum modem router, Verizon FIOS 50/50, LG HDTV 42LH90, Pioneer VSX-920 Audio/Video Multi Channel Receiver