A nightly pipeline defaults every task — simple and complex alike — to Opus with maximum thinking effort, then complains about cost. What's the actual problem?

Answer: B — It's over-served: routing everything to the most expensive tier regardless of task difficulty

Proportionality cuts both ways — under-serving with Haiku on a hard task is one failure mode, but so is over-serving simple tasks with the most expensive tier. Match tier and effort to what the task actually needs.