What each conversation costs, in real time.
Not at the invoice, and not as a monthly total that tells you nothing. Per conversation, as it happens, so an expensive one is visible while it is still happening.
What it is for
You are not billed per message, so this is not a bill. It is the thing that lets you tell the difference between a product that is working and a product that is spending.
A conversation that has cost twenty times the median is telling you something: usually that it went in circles, occasionally that somebody wrote three paragraphs about their divorce. Either way it is worth seeing at the time rather than in a month-end total that averages it away.
Why it is per conversation
Because a monthly figure is unactionable. It cannot distinguish four hundred cheap threads from three hundred cheap threads and one that broke, and the one that broke is the only thing in it you can do anything about.
It is a query over the log
Same source as the briefing and the compliance record. The meter is not a separate counter that could drift from what actually happened: it is the log, added up.
Your price does not move with it. Lewis is priced per agent, not per message, deliberately: a per-message price would make every restraint in the product cost the company money.