Are you doing this at 43' or 40'? Should I change the distance from the plate if she's throwing from 40'?A good way to tell is record from behind her. The other is to setup a horizontal string about 6ft from the net or “plate”. The string needs to be at the height of her release.
If a “drop” the ball should just skim the string and then move down. If just a low placed fast ball it will most likely go below the string.
Hope that makes sense. DD’s PC uses this during lessons and we’ve adopted it at home. Great tell when you’re trying to avoid getting hit by a moving ball.