HAHA 30g...no.
There are so many factors contributing to this, that a set number of g per serving is almost impossible to get. Your metabolism, age, gender, rate of protein uptake, time of the day ect.. all play a part. Depending on what you take it with, can also impact how much protein can be absorbed. Take whey (WPC) in water and you may get 25-30g, use milk for a higher rate, taken after workouts adds even more absorption, add more carbs higher yet, with steroids a much higher rate protein synthesis.. given the ideal conditions you could prob pull off little over to 150g, although not realistically attainable, it proves my point.
Example; A shake with 55g of protein and 30-80 carbs with some milk (est..22g+ casein) would probably be a reasonable high-protein goal. Also remember that some proteins have different digestion rates on there own such as Hydrolyzed (15min), Whey (30min), Casein (2-3h) .. blends are preferable as they combine different protein digestion times which give your body a steady flow of nutrients after the meal/shake.