Quiz: can anybody tell me why the pivot bolt needs to be in line with
 the center of the rubber bushing? :)

 Paul Lamar

So you reduce the angular component of the force vector. [It needs to be
perp to the sensor in two planes]

Jarrett Johnson

It's been 24 hours and nobody else has come up with an answer :)

The answer is the thrust from the engine would cause the sensor
beam to tend to rotate downwards and give a false torque reading on the engine.

Paul Lamar