VIMT (CVI) exists under several top-level subscription options; items the partner’s job to pick the right one for you. The actual product is licensed one of two ways though: active usage based on unique calling SIP URIs observed more than once per monthly invoice cycle; or, the count of video devices in your org. Devices outside your org joining your meeting (e.g., a business partner) also count in the former but not the latter. It’s just a question of which ends up being cheaper for your usage model. Most start with the former and adjust as-needed thereafter. VIMT has a quarterly, not annual, true forward frequency so you’ll have a good reason to switch if it’s advantageous.