Comment by bitbuilder

That's been my experience as well with projects, though I have yet to do any sort of A/B testing to see if it's all in my head or not.

I've attributed it to all your project content (custom instruction, plus documents) getting thrown into context before your prompt. And honestly, I have yet to work with any model where the quality of the answer wasn't inversely proportional to the length of context (beyond of course supplying good instruction and documentation where needed).