A knotter system of a baler for performing a knotter cycle including at least a first knot forming cycle and a second knot forming cycle. The knotter system includes a needle； a tucker arm； a billhook assembly including a billhook with a lower lip and an upper lip mounted pivotally with respect to lower lip； and a driver to make the billhook perform at least a first full rotation and a second full rotation. The billhook assembly is configured to position the upper lip away from the lower lip in a first angular range and to position the upper lip away from the lower lip in a second angular range of at least one of the first and second full rotation. The first angular range is located within a range between 0° and 160°, and the second angular range is located within a range between 160° and 360°.
