Yeah I'd assume its the same, since the guide software is the same (the descriptions of the functions on page 17 of the manual are identical to the Moto wiki), and the digital output should behave the same, it bitstreams whatever the channel's feed sends (2-channel PCM for most SD channels and Dolby Digital for HD and most premium movie channels), it doesn't process/change the audio, it leaves that to your receiver.
My home theater has a Moto DVR so that's what I've messed around with the most. My Pace is connected solely by HDMI direct to a bedroom TV so I haven't ever messed with the audio settings on it.
So as I said just set it to stereo if you find there is a difference and you should be fine. Since you have it connected via a digital connection it will switch to bitstreaming Dolby Digital when you go to an HD channel or premium channel regardless of the Audio settings.