It's not an error, Gemini 3 Pro is just somehow able to complete the benchmark while using way fewer tokens than any other model. Gemini 3 Flash is way cheaper per token, but it also tends to generate a ton of reasoning tokens to get to its answer.

They have a similar chart that compares results across all their benchmarks vs. cost and 3 Flash is about half as expensive as 3 Pro there despite being four times cheaper per token.