Speaker distances and delay times for DSP modes are not the same thing. The speaker distance setup is meant to compensate for the distance to each speaker from the listening position so that the sound from each speaker arrives at your ears at the same time. The delays built into a DSP algorithm (along with other parameters like wet/dry mix and reverb time, etc) are meant to simulate the way the recording would sound in the particular location that is being modelled.
So, if the DSP is meant to model the sound as heard in some particular concert hall, the engineers have modelled that hall and determined the delay values, time to first reflection, wet/dry mix, etc that occur in that location. The idea is to then make that sound in your living room, but your living room isn't going to be even remotely close to the location for which those parameters apply and results will vary wildly as to how it will sound.
Yamaha provides all of those DSP programs for those who like to tweak and the only way to make it sound good is changing those parameters via trial and error until you get a sound you like - but then it won't be modelling the venue it was intended to model anymore so what's the point? I avoid Yamaha for this very reason; I would rather they spend the money elsewhere than provide hundreds of DSP programs that are mostly worthless.
