This reminds me of the engineer who was called out to service a broken down appliance, looked at it, hit it with a hammer whereupon it started to work perfectly again, left and then sent in a bill for £100.
£100, screamed the disgruntled customer. I'd like to see you justify that in an itemised bill.The itemised bill arrived the next day. It read: To hitting appliance with hammer - £1. To knowing where to hit appliance with hammer, based on forty years of training and experience - £99.
It seems to me that the "fortune" you are being asked to pay is the same. It's the difference between a reliable job and the possibility of this:
Nick