good catch, they reduced the prices 75% seems like exactly in line with the speed/inference optimizations gains?

Yes. Section 5 talks about real-world deployment: 5.1: "The DSpark draft models are co-deployed with the preview versions of DeepSeek-V4-Flash and DeepSeek-V4-Pro"; 5.4: "MTP-1 represents the former production setup, having been superseded by DSpark two weeks following the DeepSeek-V4-preview release."

Lookahead Sparse Attention should be playing a big role as well, as it dramatically slashes memory consumption.