Sorry to bump an aging thread, but this is the most recent topic on torque/extensions (and I'm already signed up for GJ), but this concept makes no sense to me.
If you put an extension on a torque wrench AT ANY ANGLE, you HAVE changed the length, haven't you? Torque should be measured from the handle to *where the torque is being applied,* yes? So if you add a crows foot at 90* to the handle, you've created a triangle (and the hypotenuse of a triangle, the actual distance between the handle and where the torque is being applied, is always greater than its legs).
So shouldnt you use the ol pythagorean theorem to calc the hypotenuse of the triangle, then feed that into an 'adjusted length' calculation for torque?