Reference disc player...UDP 205 or Marantz?

There MUST be a button, either on the remote or on the front of the player that allows you to do that on the fly. I can not imagine that you would have to go in the menu to find it, and then pick only ONE layer. How cumbersome. Sorry, it makes no sense, at least from a purely logical perspective. 

I'll go out on a limb and say I'm not simplifying it.

Thanks for the clarification.

So what I am hearing you say is that UDP-205 can in fact be set up to play the stereo hi-rez layer of typical SACD which has three layers, CD, stereo SACD and MC.

What I am still not clear but will try to find out, where in the owners manual one finds direction of how to setup the player so that it would play the stereo SACD layer.

Don’t laugh, I am learning and thanks again.

I just took a quick peek at the manual. Go to page 59 and look at the picture of the menu at the top of the page - you'll see the words, "SACD Priority." On page 60, is the selection to tell the player which layer of the disc to play by default. Under that is the selection for "SACD Output" which you'd likely want to set to "DSD" if you're using the analog outputs, which I'd recommend.
The other selections for "SACD output" are if you want or need to convert DSD to PCM for an external DAC that doesn't support DSD, or if for some reason you wanted to convert DSD to PCM before sending it to the internal DAC. The extra step of conversion from DSD to PCM isn't necessary, and in my opinion, degrades the sound when using the analog outputs. I'm of the opinion that the less conversions you make of the data, the better.
When I had my first Oppo, I was overwhelmed by all the options, but after reading them a few times it starts to make sense.

I forgot to mention that there is a button on the remote to select a different layer of the SACD disc should you wish to play back a different layer than you set the player to default to.

Thanks for your comments;

Yesterday I contacted OPPO Customer Service and received the following reply;

“Under playback setup you will change SACD Priority from Multi Channel to Stereo. The player will then playback the Stereo layer or a SACD”.

I also checked the layout of remote control, there are 35 buttons listed but I do not see any button for selecting the SACD Stereo layer on the remote.

So far so good, the only remaining question is PCM/DSD. On page 60 this is discussed but the choices listed are for HDMI output, in my case I do not want to mess with HDMI but instead use analog two channel RCA outputs.

Vahes,
It may be called something like "layer", which is how it's designated on my Marantz. I'm sure it could be called something else as well. Maybe in the oppo's case, it's something a bit more esoteric. I'm sure it's there.