A tweak to the Aristotelian account of individuation

The standard Aristotelian story about individuation of finite substances is two-fold:

1. What makes x and y distinct when x and y are members of different species is their difference in form

2. What makes x and y distinct when x and y are members of the same species is their difference in matter.

But I think a slight tweak is in order. Suppose Alice and Spot are both members of different species and have a difference of matter. By the standard story, what accounts for their distinction is just their having different form. But it seems right to say that their difference in matter is also sufficient to distinguish them. The distinction between Alice and Spot is overdetermined by a difference in species and a difference in matter.

If so, then intead of (1) and (2), we should have an inclusively disjunctive account:

3. What makes x and y distinct is that they have a difference in form or have a difference in matter or both.

To make this account work even better, I will stipulate that the difference between an immaterial substance (say, an angel) and a material substance (say, a human) also counts as a difference in matter. Thus, there are two sorts of differences of matter: two things having different matter, or one thing having matter and the other not.