It must be a DVD-Video disc then. A lot of newer releases say DVD-Audio but are in fact DVD-Video discs. If you can see both DTS and DD you can select DTS and it will extract that. Is there a difference between the DTS decoder in the Oppo and that used by DADAE, you wouldn't think so but maybe?
No again. It is a DVD-Audio. Here is the DVD-Audio layer you get when you open normally with DVD Audio Extractor.