Every tier is served by the same network. A record that reaches an evaluation account traveled the same path, carries the same provenance, and was evaluated by the same models as one reaching an enterprise account - we do not hold back quality and sell it back as an upgrade.
What changes across tiers is scope: how much of our coverage you take, how far back through point-in-time history you can reach, and what we commit to contractually on latency and support. Those are the two axes that actually cost us money to widen, so those are the two we price on.
There is no per-seat component. A three-person research pod and a forty-person desk pay the same for the same coverage, because charging by headcount would penalize you for putting more people on the data - which is the opposite of what we want. Volume beyond the enterprise band is negotiated as capacity, not as licenses.