I would agree that describing a cluster as active/active/active/passive can be more descriptive than saying N-1, where N=4 - depending on the audience. Both terms are in use and neither is incorrect. Depends on what you're describing.

Quick poll of the system engineers at the client I'm onsite at today gives a mixture of answers. It also depends on how large N is. If N=8, no-one's going to say active/active/active/active/active/active/active/passive....

Just one more example of duplicate nomenclatures with people preferring one over another that serves to confues those who aren't experts.