ALso, I had the same problem awhile back. Bow was shooting BH and field points exactly the same and, once I put on new string/cables, couldn't get them to group the same. After a little break in period, however, I did some major retuning on the bow - twisting cables and strings to restore ATA and brace height, as well as moving the rest and nocking point a bit- and wound up with things grouping the same again.This issue may not have anything to do with the arrows or fletching.