Thank you cornfed. You saved me a lot of typing. I had my bow shooting both FT and BHs perfectly and decided to go get a 3 pack of lighted nocks for hunting last year. Put them in, shot at about 10 yds to make sure they worked. Then went out and shot at 20 and 30 yds and I could not believe the difference in POI and the way the group enlarged.
Needless to say, the nocks came off and now for visibility I use crested arrows with either white or floruscent green fletching. Impact is just as easily seen.