mrgribbles since you have a 7.1 setup you might not be aware that for those of us with 5.1 setup, you CANNOT choose PLII (non x) modes when receiving a DD5.1 signal. So whether PLII is an "extension" of regular dolby decoding doesnt really matter in this context, since onkyo's implementation does not allow it to be selected on an already 5.1 signal. Turn off your back surrounds and try it out for yourself

Also regarding listening mode presets, you will also notice there is not separate sections for DD 5.1, and DD2.0 - there is just a Dolby Digital section (and this appears to assume a 5.1 input, since you cant choose PLII Movie/Music mode for the preset). As such, you can only set Dolby D as the preset for Dolby Digital... not sure how/where you can set the default listening mode for a Dolby 2.0 signal - however at the same time, my receiver seems to always go to PLII Movie mode when i do receive a DD2.0 signal - i suspect DD2.0 is always handled in a "Last Valid" arrangement, despite there not being an actual listening mode preset section for DD 2.0.
Now, adding my 2c to the Listening Mode Preset discussion, a poster earlier asked if they could not choose Dolby D mode for one of the inputs, because he "had already chosen it for Dolby Digital". It isnt a case of only being able to assign a certain listening mode to just one audio signal type or anything like that, it is actually that the onkyo is "smart" and will only provide certain listening modes for selection, depending on the input signal... Thus your options in the preset menu reflet this (ie yo ucan only pick a mode valid for that input type). In terms of listening modes on these onkyos, there are a bunch of listening modes that are available on all signals - these include Pure Audio, All Channel Stereo, Direct, Stereo, Mono etc plus the "built in" onkyo ones like Theatre Dimensional, TV Logic, Orchestra and so on (dont bother using these last ones like TV Logic etc... Pure Audio and Al lCh Stereo are useful though). Then there are the proper "decoder" type listening modes, which will depend on what the signal being received is... And you usually get a THX version of somethignas well, since the 705 has THX certification. For example if you are receving a 2 channel signal (eg 2 channel PCM or D.F Stereo (ie red+white analog RCA input)) you have all the "expand to 5.1" modes like the Dolby PLII Movie/Music/Game, the Neo:6 and Neural THX stuff, plus the THX versions of PLII etc and THX cinema. But if receiving a DD 5.1 signal, you can only choose Dolby D or THX Cinema, in addition to the always available listening modes listed earlier. When receiving a DTS signal - you can only choose DTS and THX Cinema, plus the always available ones mentioned earlier. With Multi Channel PCM (ie more than 2 channels of PCM over HDMI from a BluRay player or PS3 etc that does the decoding itself and sends PCM) the only real choice is MultiCh, plus THX Cinema and the always selectable ones mentioend earlier. DTS-ES has the "proper" DTS_ES one, plus the regular ones and probably a THX Cinema... DD EX same deal... Dolby TrueHD has "TrueHD" mode, plus the regular ones... DTS-HD has DTS HD MSTR plus the regular ones and so on. Im sure by now people are getting the picture

If you start from Last Valid and scroll to the right, i find you get Pure Audio then stereo and mono, and then you hit the "whatever is appropriate for this signal" selections, like the Dolby D, DTS, MultiCh and whatever else.
Note that all of this refers to when you have a 5.1 system. If you have 7.1, the PLII
x modes are available for most input signals, since they are usually 5.1, meaning the "expand to 7.1" options are available to you (just as the "expand to 5.1" options are available to you if you have a 5.1 system and are receiving a less than 5.1 signal. Hoepfully that gives some insight into how the listening modes work, for some of the newer owners