Actually I would say most of the resemblance you see is the way I tweaked the profile. I turn down contrast typically, because the profile is already so contrasty, and pick a color filter to suit the subject, so certain elements like the sky are affected in a way that probably comes close to what the engine does in hard B&W.
Also, I move away from big, blocked out shadows because I don't care as much for them. I try to make hi-contrast B&W look as much like the film that I develop myself as possible. So I have the shadow recovery/compensation set to high, and the overall profile set to +3 high key, other adjustments as needed. That way the shadows have definition usually, and as long as I slightly underexpose the image, I can still get bright elements without being pure white. I'm essentially kind of toning down the profile a little bit.