When dealing with swing weight, you need to take into account the weight of all components. The grip, the shaft weight and length, and the head weight. Changing any of these will change the swing weight. Check the weight of the current shaft. If it's different from the new shaft, you will need to make adjustments elsewhere. If you are changing weight and length, you'll need to weigh all components of new set up and make adjustments to grip weight, head weight or both.