I guess my question for the OP would be....were there any "symptoms" exibited by the gun that would indicate there was a problem with the single action prior to your test for push off?

The S&W armorer's manual describes the pressure used to test the hammer trigger interface as "nominal". (whatever that is) Having some experience with testing for, and repair of this condition, I would estimate this pressure as 4 - 6 pounds. Excessive pressure should not be used as this can damage the very sharp bevel on the trigger.

Revolvers suffering from push off will usually also exhibit specific symptoms of the problem, including a "mushy" (opposite of crisp) and very light SA trigger let off.....below 2.5 lbs.

Symptoms can manifest themselves after years and years of heavy use, build up of dirt, debris or old/improper lubricants.....or from modification of factory installed components, including the mainspring, mainspring strain screw, rebound slide spring, or the hammer/trigger SA interface. (or combination of these factors)

Since the term "nominal" pressure is subject to a wide range of interpretation............if there are no other obvious mechanical or felt symptoms indicating a problem with the hammer and trigger, and the internals are confirmed clean and properly lubricated, perhaps a better test to check the integrity of the single action for most revolver owners would be to simply use a quality trigger pull gauge. Factory minimum recommended SA pull is 3 pounds.

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Ret. LE, FA Instr, S&W Armorer