OBV used to be used in different ways.
Granville had one use for it and Larry Williams (I think it was him) used a
different formula to obtain what he called OBV. I don't remember the
formula any more as I haven't played with it in years. I do remember that
it gave better results than Granville's straight OBV,
There was a theory in the late 60s and early 70s
that you could judge how much volume it would take to move a stock an 1/8, 1/2
or point. On balance volume fell out of favor for a while after Granville
predicted a massive bear market. The next morning the market dropped
substantially and then it rallied and just didn't stop. After that
Granville lost his ability to move markets or peoples opinion.