I don't think you are hearing the usual magic of the B3K > VT Bass combination there IMHO.
For me, the fun bit of using a dirt pedal like the B3K is what it does to the twang at the beginning of the note. The treblier that twang from the bass, the more gritty/bitey the pedal. If you have a less trebly / twangy sound from the string, you tend to get a plummy / buzzy / farty sound, not a bitey raw sound.
Of course some people do like 'buzz', and some songs call for it, but I don't think you're getting the sound that most people enjoy from the B3K.
That's what I've been wondering. I'm going to switch to rounds in a couple of days and record a new sample to see how it compares.