Cost comparison: Opus 5.5 tokens 1.6x cheaper than V4.1 Flash under $20 plans
The author calculates $20 buys ~2.9B tokens on Claude Pro vs ~1.8B on DeepSeek V4.1 Flash because ~96% of billing is cache, yet at API list price those tokens cost ~$1,650 vs ~$33.
This cannot be true. Claude Opus 5.5 is 1.6x cheaper per token than DeepSeek V4.1. Same workload, same $20. $20 of Claude Pro: ~2.9 billion tokens. $20 of DeepSeek V4.1 Flash (off-peak): ~1.8 billion tokens. $0.0069 per million tokens vs $0.0113. The lab with the higher API price sells the cheaper token. At API list price, those same 2.9 billion tokens cost ~$1,650 on Opus 5.5 and ~$33 on V4.1 Flash. 50x the other direction. Both numbers are true, and for the same reason on both sides: ~96% of what gets counted is cache. On Claude that is cache reads, the agent re-reading its own context at 5% of the input price. On DeepSeek that is cache hits at $0.003/M. DeepSeek at least publishes the shape of it. Its DeepInfer release: 155 trillion tokens a day on one cluster, 96% KV-cache hit rate, ~$38 billed per GPU-hour at off-peak prices. DeepSeek sells the same work 50x cheaper on paper and 1.6x more expensive in practice. What is the correct pricing model here?