When a stock moves towards oversold (too many sellers), sellers are in control and the stock typically keeps going down. Until it moves back out of oversold. That indicates a reversal is coming. As the buying begins to take over, the oscillator moves higher and higher until (ideally) it gets to Overbought. Then it keeps going up until it reverses again.
It doesn't always make it to either extreme before it reverses. Therefor, when it is in the range of the extremes, price moves can often be more powerful, in the direction of the trend.
oversold is a condition in which the stock is at or nearing a point where the selling should slow and turn into buying and start thestock heading toward the opposite condition: overbought.