It's just that I wanted to emphasize them more, I separated them and made seven reflections. When you think about the actions and results of actions reflection, and when you think about the Compassion and Equanimity reflection, Compassion and Equanimity is actually a subset of the actions and results of actions, of the Kamma reflection. It's really one part of it.
Death itself is one part of impermanence. However, death is a very major one and that's why I wanted to separate them so to give more emphasis to death by itself, a subgroup of impermanence. Then at other times to think of impermanence just in general terms regarding everything. I just wanted to emphasize more the death part of impermanence.