Nut busting torque tests the tools capability to remove a bolt that's been tightened using techniques apart from the tool itself. The problem with this is there’s presently no industry wide standard for testing or posting torque rankings, and variables like bolt size and type, thread conditions, air pressure, CFM, etc affect the outcome of the test. This gives manufactures a way to test tools with deceptive techniques that permit them to boost the marketed torque rating, but those techniques won't give you an accurate portrayal of real working torque. Maybe, you have the ability to get huge number of nut busting torque every now and then, given a particular set of conditions but that is not the real working torque the tool is continuously able to deliver.