Gpt 5.6 Luna cache read is $0.02 per mtok

V4 flash cache read is $0.0028 per mtok

That's not "a bit cheaper", just saying

That's a good point. Yeah their caching input is insane.

DeepSeek v4 API rates are only matched by Xiaomi's MiMo v2.5 series. Quite similar in capabilities too (at least before today's update).