Generally swing weights on drivers tend to be a little higher than on irons but that is due to the length. Swing weight is not a real weight indicator like total weight. Your driver is lighter in total weight than your other clubs, I would assume, and again the D6 swing weight is a reflection of the length of the club. That being said, some players will counter balance drivers, which lowers the swing weight and raises the overall balance point of the total club. It is believed that this can help increase swing speed for some players. Many shaft companies make a counter balanced shaft (shaft with a higher balance point) and have data that for some players it does improve the swing speed. You can do it and give it a try, but you don’t want to sacrifice club head feel. If you do it and the clubs feels too light, you have probably added too much weight to the butt end.