There are 2 alignment method options for Face Crop. The default is “Chine to top of Subject” and that looks like what you are using. From what I can see, Face Crop worked correctly for that algorithm in you batch. What that alignment, it will align the chin and top of the hair within a certain space. So for all of the images, the chin is in the same location and the top of the hair is in the same location. However, for people with taller hair, it has to scale down to fit the hair to the top line and keep the chin on the bottom line. The benefit of this method it the top margins remain consistent and also the chin placement remains consistent.
The other alignment option you have is the Head Only alignment. This aligns the chin end eyes to same location for all images. So the face features are scaled the same for all images….. as much as possible. However, the disadvantage of this is the top margin will vary image to image. People with tall hair or tall forehead will have less top margin then people with short hair. Also, if some people are tilting their heads down more than others then it really skews where the top of the head ends up in relationship to the chin and eyes.
So you can switch the option the run Face Only. However, the yearbook people will probably then complain that the top margins vary between images.
It is impossible to keep the top margins the same for all images with varying hair styles and also maintain the exact same scaling too. The math of that doesn’t work. So you will need to pick one or the other. The vast majority of people prefer to keep the chines aligned and also the top margins the same. So that is what the software does by default.
So I suggest switching the algorithm to Head Only and running a batch to see which results you like better. You may need to also create a new preset with slightly different values to get the Head Only to give you similar scaling than shin to top gives you. The same preset may yield slightly different scaling. So just try Head Only and play with the presets to see if it gives you better results for what you are needing.
My guess is that the yearbook people will complain more about the top margins then they would about the scaling. however, the choice is yours for which method to use.