BELOW NOTES FROM NAWCC THREAD, GO TO SCHATZ WITH THIRD WHEEL MAINTING POWER THREAD FOR THE REST. The third wheel spring does require another click or two on the mainspring for the "run test" to work. It does not require that it be fully wound, in fact that will occur only when the mainspring is about 1/4 wound. This spring didn't do what they had hoped, that is to provide a flatter performance curve to improve timekeeping over the long run.

The third wheel spring, once fully wound, only starts to unwind when the Mainspring is about 80% unwound, then continues slowly unwinding until the clock stops. The one thing it does do is add about 30 days run time to the clock. As Shutt has explained there is no particular problem I know of with having the spring there so long as it isn't broke

Four hundred day clocks don't need maintaining power. There is no interruption of torque to the train during winding the way there is on clocks with a fusee, or tower clocks etc.