Wow theres a lot here to comment on...I, for one, do not agree with the massive amounts of protien some take in. I dont think you can expect your body to take in much more than 40 grams per meal. If one eats every 2 hours (minus 8 hours at nite to sleep), thats 320 grams of protien a day. I believe most ppl gain more when they take in so much protien is because their calories are so much higher.
Your body also has a way of evening shit out. People who live in high altitudes use oxygen more more efficiently than those at sea level. The same is true for protien. This is why, lately, I've been cycling. A couple days of really high amounts of protein, then a few at lower amounts.
There is no way you can change the amount of protien your body extracts from the food you eat. When you are 200 lbs, your body can absorb just as much protien as if you were 250 lbs. The difference is how efficiently your body uses the protien. Here is where the cycling comes into play, again.
Personally, on my high protien days I take in more shakes in addition to my meals. On my low days, I take in no shakes and eat as much as I can.