In the "optimal latency" case you can start heating the 2nd cup immediately after the first, then it's ready after 7 time units, for average of 3 time units per

In the "optimal latency" case you can start heating the 2nd cup immediately after the first, then it's ready after 7 time units, for average of 3 time units per cup, which is better throughput than the "optimal throughput" case (3.25 t/c).