Played it through. All five came back, and day 3 (the watch) is the whole game in one customer: 'Ask who wore it before him' repairs nothing and it is the only fix that brings him back, and the tell points away from the object entirely. That is the thesis and it lands.
The crack is that the returning fix is only ever legible in hindsight. 'What they actually wanted' is revealed after the choice, so a miss only ever says 'not returning', which reads the same whether I misread the object or ignored the tell. Those are different mistakes and the score cannot tell them apart. Give the miss its own mark (they pay and leave, they take the receipt, they do not look at you) and the lessons get real.
Second: the parts economy never bit me. I finished with coil and seal to spare, because the returning fixes mostly cost no part, so the counter implies pressure the game never applies. If parts matter, make the human fix cost more than the mechanical one and the choice gets teeth.
Good thing: scoring 'did they come back' instead of 'did it work' is the best idea I have seen in this jam. I want a longer shop.