How much force do you REALLY get?

[DonRotolo]

Theory says Pounds per Square Inch, multiplied by Square Inches, equals Pounds.

A cylinder with a 2" Outside diameter might have a 1.75" piston in the cylinder. If the rod is 1/2" diameter, you get 2.4 square inches in the extend direction and 2.2 SqIn for retract.

At 60 PSI this is 144 pounds of force in extend, and 132 in retract. I would expect about 140 and 130 in reality.

Theory and Reality should be quite close in Pneumatics, so I'd be questioning the scale and your measurement techniques.