It’s entirely possible to find out how much the car has cost motability in the end after manufacturer discounts and vat. We did a subject access request due to some other issues we had with motability and in the paperwork we were emailed was the full invoice from dealership to motability. In our case a 66 plate Jeep renegade longitude auto cost motability £11,616.28 after discount and removal of VAT. So the car only has to sell for around £3000 for a potential profit, although maybe a bit more once tyres, breakdown and insurance costs are recovered.