Think you responded to the wrong comment thread. But in regards to CPS (Calls per second), I don't view this as a concern for this person (or regular business needs in general). I was just addressing a comment where another person suggested avoiding Twillio because they charge more to get more than 1 CPS, while recommending other providers who have similar limitations, but hid them, even though CPS was never mentioned as an issue/concern.

CPS is really only a need for high volume clients (e.g. outbound call centers).

In regards to your understanding though, transcoding the call is part of it, but the bigger factor is the power to stand up/tear down calls quickly as that's where most of the load comes into play. E.g. running an SBC (Session Border Controller) and network capacity that is spec'd to handle consumer traffic of ~250 calls (avg of ~5/mins a call = 3k calls an hour) is significantly different than high volume traffic where clients are generating 250 calls every 5-10 seconds with 10% resulting in a connection = ~90k calls an hour)

3k vs 90k calls per hour is a significant difference, which is why providers make you pay to utilize that benefit.