Market work by short and long players positions. By commodities, players buy or sell positions based in market expectations. The volume of negotiations defines the optimum point to buy or sell. It means how much more volume in a price line, much of the players thinking this is the real value. So, in this indicator I calculate the volume of trades for some price line. And divide it to the total volume, to define whats the historical price line optimum. The diference between the actual price to the historical optimum trade, define some directions of the market. Some times the price is bigger, and sometimes it is smaller.
By experience, after some times the price is deviated to the flow price, it will search a compensation, starting a reversion movement.