Try and get them to fly better, but you may just have to live with it. Could be arrows or part of the arrows or the bow or a host of different things. Do you want to start buying new stuff and trying different combinations till you find the right mix. Few of my arrows fly exactly the same. One will always go to it's spot and the next to it's but they seldom go to the same one. Pick one arrow and see what it can do. When it hits the same grab another. It probably won't and thunder heads because of their design exaggerate the smallest problems.
I don't try and make mine hit the same because they aren't. I try and get them to fly straight and quiet. If they hit the same fine, if not it's a compromise for a point and a head to hit the same. Why do that? Let'm fly free and happy not held back like some smart kid in a class.
A used head isn't always true anymore and can cause poor flight. Bought 50 THeads a few years ago for just over 50 bucks. Use them a lot. Kind of know about them. They also don't weight what they say they do. The 125 I think is over 130, your point isn't. 6grns. can cause a Thead to exaggerate a drop. Adding weight to the tail believe it or not can lift the arrow.