With the earlier/thinner head gasket, once the gasket is fully compressed (@30 ft lbs) you then begin to compress the head and it is basically incompressible. At that point most of the torque is merely stretching the bolt. When you reach the final torque the bolt becomes a spring holding down the head.
The key to the whole process is taking the bolt to the right torque value. Typically you take a bolt to a value that is less than results in permanent elongation. It seems as these bolts are worked closer to the permenant elongation value, thus, the reason the Gen 1 bolts cannot be reused.
A similar analogy is a spark plug with a gasket. It might take over one turn (after hand seating)to compress the gasket, at that point it will take less then a quarter turn to reach the proper torque value.