In a seeded 1,000-customer model where each plan earns $50,000 a month, flat pricing lost money on 77 customers and seat pricing on 106 at a unit cost of $0.02; usage and hybrid plans lost on none.
Pure usage pricing made 1,410 of 5,000 monthly invoice changes jump by more than half; a $19 base with 500 included units cut that to 759.
Cashier 16.9.0 sends one HTTP call per reportMeterEvent and a new random identifier each time, so batch usage locally and pass a fixed identifier to make job retries safe.