Yeah, all these GPT-3.5 and GPT-4 models have a large amount of fine-tuning on top of them. I can see why it’s not an option right now. (fine-tune some other fine-tune?)
Maybe if they have base GPT-3.5 and GPT-4 models available, then they will essentially create a similar layer, but only off your fine-tuned inputs. That would be cool!