manipulation and patience
I do not think the trading pattern is crazy, it is a matter of institutions accumulating positions from other institutions by exchanging stocks they wish to have positions in with some fine-tuning of the stock price. Sven's figures show that on average up volume tick is 11,000 shares (5 moves) down tick volume is 3,500 (11 moves, 4 of which were 500 shares are less). Let's say I own AMA-X but am not thrilled about it, somebody else has AOS which I do want at a cheap price and they are willing to exchange for AMA, then controlled release of stock will accumulate the desired positions eventually. With patience AOS believers can benefit from this manipulation, more of a problem if you are a seller. Bashers help in this farce. Apart from AMA, other examples UMJ, CRD, WM.
I can't prove it, but if I was a professional I would be talking to my peers and indulging in the same shenanigans.