1. The values in your screenshot for headsize and top margin are different than the settings for that. In your screenshot, you have the headsize set to 50% of the frame height. The waist up preset is 32%. the top margin is also different. If you saved over the preset the you can reload the factory settings under the manage presets button.
2. The presets were created wihtout graduation caps assuming that the head would fill the space between the guides that you see on the screen. You have the Face + Top algorithm selected. With the graduation cap, it then fits the head plus the cap between the lines so it has to scale the image smaller to do that with a cap. If you select the Head Only algorithm, the the image will be scaled larger. In that case. it will put the chin at the bottom line and guess at where the top of the head is for the top lin. This will push the graduation cap over the top line so you’d need to increase the top margin.
Keep in mind that there is no way for the software to detect a waist. It scales by the head, and also the top of the hair or hat if you have “Head+Top” selected as the algorithm.
What you will probably need to do is just create your own preset that works for your images. I would probably still use Head+Top and then increase the head size and adjust the top margin so it is what you want. You can save a preset with whatever values work for your images.
Just keep in mind that if people are wearing the graduation caps differently then it will affect the scaling. So if some kids have the caps tipped way up, the it would have to scale smaller to fit it in.
Another too, for those poses, if you want to use automatic cropping, you really want to shoot looser in camera to allow the software rom to work. I can see from those images that they are already cropped pretty tight in camera. In those cases, the software has different modes for how to handle it in batch. the default mode will force it to just scale tighter in order to remove all empty space. So it ends up causing more variation if some images needs cropped tighter to remove the excess space and some don’t.
last thing, Face Crop was really more created for headshots. The wider you try to scale, the lass accurate it becomes because not everyone has the same head vs. body size proportions. Also this varies by age. Toddlers are like bobble heads with huge heads compared to the rest of their bodies. So waist up cropping for an adult becomes thing up for toddlers when using the same settings because it is scaling based on head size. Also, even within the same age group, there is a lot of variation. You can have a person who is 5′ 3″ tall have a larger head than a person who is 6′ 5″ tall. So again, when scaling based on head size, the waists will not line up tin the same spot between the images. So for these reasons, a face cropping software is really most accurate for scaling with head shots or head and shoulders.
Hope this info helps