If I need to turn a bolt to 50 ft-lb with a beam torque wrench, and I turn it until the needle points to 20, then I need to stop applying pressure for some reason. Do I just apply another 30 ft-lb the next time? Or do I still need to go to 50?
If that would be possible, every 3-year old could fasten the bolt. He just has to try 100 times with 0.5lb-ft.
You have to apply the full 50lb-ft, regardless of the torque applied before!