COST-ANALYSIS

DeepSeek V4 Pro lands an 80.6 on SWE-bench Verified in Max reasoning mode at $0.66/$1.98 per million tokens off-peak, and Flash runs agent inner loops at $0.22/$0.66. Here is the worked cost math, the Flash-vs-Pro split, and a clear guide on when to route to DeepSeek instead of a frontier model.

Open weights are free to download, but inference is not free to run. Here is the honest break-even math on when self-hosting GLM-5.2, DeepSeek V4, or Llama beats paying per-token API prices - GPU rental and ownership costs, real throughput, utilization, the crossover in tokens per month, and the hidden ops bill nobody budgets for.

Fable 5 lists at $10/$50 per million tokens - twice Opus 4.8. But list price is the wrong number. Here is the cost-per-outcome math that actually decides whether the upgrade pays.

DeepSeek V4-Flash costs $0.28 per million output tokens. Fable 5 costs $50. That 178x gap is real - but so is the quality difference. Here is where it matters and where it does not.