I think if there are invites and the freelancer replies, it's counted as an "interview." You can't go by those numbers too much because they don't seem to be real-time. They seem to be updated after a certain amount of time.
Eric S wrote:
I submitted a proposal for a job that indicates there are four applicants and four interviews... I have not been interviewed. What's happened here?
That means the client declined or archived every applicant apart from the ones the client is already interviewing.
This means you are out of the running, the client archived (or declined) your proposal.