I'm pretty sure the analog audio outputs are always active, and the sound for it downmixed if needed. However, I have noticed that output from the analog audio outputs lags a little behind the digital audio outputs. It is slightly noticeable with lips not quite in sync, but not bad. If you have both the digital audio and the analog audio going at the same time, you can hear a very distinct echo. At least that is my experience, not sure it is the same for everyone.
Still like to know for sure the DTS downmix to RCA stereo. Probably we're able to live with a very small delay.