A really old indicator as well, thus i have no much ideas of what is going on with it, but i know that those bands returns good reversals points. The indicator don't use standard deviation, instead its a simple differencing of the price and the price length bars back who will provide a dispersion measurement, thus the name auto-dispersion.
The Indicator
The smooth parameter allow the band to cross the price, if smooth is low the chance of crosses are lower.