When the bands are expanding, "opening the jaws" as some seasoned traders like to say, this is not the time to treat a band tag by itself as an overbought / oversold signal and trade a reversal accordingly. As the bands expand, it is often in conjunction with a a trend move. Sometimes, fakeouts can occur in which price tags a band in a direction counter to its ultimate move. But the overbought / oversold signal of a band tag works best only when the bands are essentially stable and flat, usually contracted, and moving sideways along with price action trading in a range, the tag does not result in a decisive move where price starts walking the bands and the bands start expanding.