RR and Greyrider are talking about two different things. Even if both are from the same manual.
RR is describing early forms of TMA based on rate of bearing change. in essence this is the same as the method of TMA described by Aaron Blood in his MoBo and by mittelwaechter with his method.
This method that RR is talking about predates ekelund ranging and whatnot and will only provide relative course (note not true course, unless you are staionary), not speed or range.
Greyrider's formula that seems to work is nothing other than the necessary result of basic trigonometry. This formula has by other names been very well known in this community for years already. it is simply that knowing your own speed as one leg of the triangle, the bearing to target and the aob of target, the target speed makes the other leg.
Hell you can even do it without a constant bearing with one of these, but then you do need at some point in the process a range.
http://www.subsim.com/radioroom/show...ighlight=iswas