As Tusker said, It's probably not the ferrule, it's the blade.. It's just that on a screw in there is little you can do about it..
When I align broad heads, I do not spin them.. I have a jig (Pair of V-blocks and an angle plate) But you could improvise with a shoe box with notches cut on either end and paper stuck to the wall. I slide the broad head forward till it touches the paper, Typically a two blade the blade is vertical.. Then I pull back and rotate it 180 degrees.. If it is aligned, they will touch in exactly the same place. If not, you will know which way the blade needs to move and how much, which is a big help as opposed to just twisting.. A couple of tries and they should be "Spot on" Twist them like a top and watch for wobble.
If the arrow is straight, the only things I have seen affect them negatively is misaligned head or knock.. Both are dissaterous