I haven't even added Strawberry support to my app yet, and so haven't checked what it's context length is, but you're right that additional context length is a scaling factor that's totally independent of whether CoT is used or not.
I'm just saying whatever they did in their [new] model, I think they also added CoT on top of it, as the outer layer of the onion so to speak.
You don't see the scaling with respect to token length with non-FT'd CoT like this, in my opinion.