I've heard that MND does indeed affect the light damage that these bolts do, from another poster who experimented with lots of +MND gear. Of course, MND won't affect your accuracy or physical damage, so it's probably not worth wearing a Justice Badge instead of a Ranger's necklace...
I started this at 7. Most broke and after they did i got mad. Then i finished my supplies and my level grew. After that i made Holly Poles and they raise my skill up to ten easily in increments of .2. Its still at 10 so i dont know if it still works.