Have a look at this..
http://www.subsim.com/radioroom/showthread.php?t=213971
There's an adjustment error in the last stage, but up to stage 5 you should get within +-1 knot of ship speed and low AOBs.
At AOBs at 45-90 you should get within +-0.5 Knots.
I'm still busy with the last correction stage, but have parties to attend to

(aaahhhh ...the life of the rich and famous

)