PEH, I do not understand your question....maybe you needed more vacation time....

The piston ( and for that matter the head, what ever surface of the bore ) has what ever number of pounds of air pressure you put into it with your air compressor....

That is referring to EACH SQUARE INCH... thus... Pounds PER Square INCH....

But the force on the piston pushing towards the crank.... which we are concerned with possibly turning the crank when we are not expecting it... is the number of square inches on the top of the piston times the Pounds per square inch...

Thus the force pushing down on the top of the piston is 1200 pounds...

One is referring to each square inch.. one is the total pushing on the piston...

I expect when you think about this you will wonder why you posed the question....

Was this all about you challenging my use of the word pressure for downward force instead of 'force'?