Russ, please start checking out some other sources than your exercise physiology book. You did the same thing in the other thread I read. Please read up on current studies through pubmed or science direct or something like that. Anything can get published as long as it relates correctly to the group being studied. Hardly any studies ever make inferences on to what else the study relates to. Many studies are flawed, yes. Many studies still get published, yes.
I've read in a few places, 12g of whey can be absorbed an hour. It really depends on how long the protein is actually in contact with the intestine where absorption occurs. Things such as fiber, protein type and fats can slow down or speed up the amount of time in transit.
Furthermore, there have been some studies that show certain proteases can help increase the amount of protein absorbed. The truth is, the amount absorbed is probably more than they think but less than the amount bodybuilders believe. The other question is, does the body really need that much protein to build muscle or not. Until we can do more human studies that aren't invasive or have better research methods, we won't know the answer. Right now there really don't exist any kind of tests that can be done to determine exactly how much is absorbed or needed.