Quote from version77:
In one of his recorded seminars he gives out some formula or
whatever he says you need that isn't in the book. So, you either
need to watch his seminar or get the data from his website.
Book is incomplete in and of itself if you want to trade his method.
I listened to a recent webinar presentation he did where he suggested using 20% of the ATR of 10 or 20 trading days as 'A' value.
MBF responded to a question on ACD that, as Mav74 notes, it should be used as a bias and "you cannot use it as a buy/sell..."