1970 340 oil pan gasket help

I wish I had read this a year ago. Back then I took the pan off after having already torqued it down after the cork gasket slipped out under pressure in one corner. The second time it did the same thing to me, but I said the heck with it and installed the motor on a wing and a prayer. What I still want to know is why/how the factory torque spec seems to be wrong?