Woogie is sort of right, the off-set 'step' is infact what is used to induce the back spin on the bb to raise it to the top of the barrel, a bit like our 'normal' nub style hops.
Most modern day users of the LRB just set their normal hop so that it adds a little flick to the bb to produce the same effect.
With my experiments with the long hop nub combined with the LRB I found you don't need as drastic a curve in the barrel to achieve similar effects.
As I explained above I simply set the long hop to give best flight then added LRB effect to increas range, but not so much as to make the flight follow a strange path.
I'm not familiar with the hop half way down the barrel your describing, but at the time I was doing my research I was in the 'LRB zone' so didn't look at much else
It sounds interesting though and might be worth persuing if a suitable weapon and system could be built. I'll have a think on it and see if I can come up with some theories..... Do you have a link to the article you were looking at please chap?