The billing unit
An MLS Genie™ subscription covers a website. Most platforms in this category sell a seat — a login for one agent — and the bill grows with the roster. Starter, Agent and Agent Pro do not: the tier is the tier however many people log in. The Team tier includes fifteen agents, and each agent beyond that is $95/mo.
Why it is priced that way
What the subscription runs is a site: the MLS feed, the listing pages, the area pages, the search rankings those pages earn. Those exist once for the business, not once per agent, so charging per agent would be charging repeatedly for one thing.