No, sorry Sherman. You are not correct. The force exerted by the servo is measured in in/oz. A servo that is rated at 42 in/oz will exert 42 oz of force on the pushrod if the pushrod is mounted 1" from the center of the servo arm. It will exert 84 oz of force 1/2" from the center but only 21 oz of force 2" from the center. Try it if you like. Fasten a 6" stick to the servo arm and see how much force it takes at the end of the stick to stall the servo. (7 ounces, actually. If your analysis were correct it should take almost 16 pounds to stall it.)

Math wise, the ounces times the inches will always equal 42 for the servo in this example. (42*1=42, 21*2=42, 84*.5=42)

So basically, at the servo, it is the opposite of what you said. Your analysis describes the control horn end of the pushrod, where the force is coming from the pushrod rather than being put into it. That is why you want the pushrod as close to the center of the servo arm as possible and as far away from the center of the control surface as possible.

Jim