Okay, yeah, I understand what you are saying. I thought initially you meant that there are other disorders that have alters other than dissociative disorders.
Rightly or wrongly I personally would only call fully dissociated self states (i.e. those that would warrant a diagnosis of DID) "alters". Other dissociated self states that don't have a fully separate sense of self-identity I would call "parts of self".
Having said that, I most often use the word "parts" to describe my fully separated and independently functioning alters.
Oh, no, I am never inconsistent at all.