It shouldn't be. Your fixed heads and field tips should fly the same but I'd guess they won't. At least at first. It will depend on the type of broadhead you use and how well your bow is tuned. There are some broadheads that may not fly same as field tips due to their design or size, but many can and will fly the same as field tips. The smaller heads (cutting diameter 1 1/8" or less) will have a better chance of flying with the field tips. While the smaller heads may fly truer, it won't mean your bow is tuned. I, myself, like to use larger heads that I know do not fly the same as my field tips to help me fine tune my bow. If I'm getting good groups with field tips and maybe small fixed heads but larger heads, say drift left, I will make adjustments until the larger heads are flying same as the field tips. Usually, although I may have been getting good groups before the adjustments, I will notice they get even better after. Good luck.