[krazzdav]

Has anyone else had a problem where Xentry XDOS works fine in general, but for some car models instead of opening 'Xentry Diagnostics' section of the program, it opens 'DAS' instead?

If I use the Xentry on my W212 (2014) it works fine - I'm able to select the model and by clicking 'Xentry Diagnostics' .... Xentry Diagnostics open, but for X164 (2010) it doesn't work like that, instead, every time I click 'Xentry Diagnostics in the Xentry program after selecting the make and model - DAS opens.

Is it some kind of a feature or a bug or is there something I'm missing?

That's normal; older vehicles only need DAS and I had the same thing happen for my 2010 W204. SIM mode does the same for your X164. If you look in XENTRY when it opens DAS it should say that is the "active diagnosis application is the Diagnosis Assistance System"