It would be interesting to see what the contract involves and covers, operating an aircraft involves parking fees, maintenance and insurance costs, sitting on the ground means increased parking costs and increased maintenance costs per hour of utilisation. There will be an optimum hours per year flying to reduce the costings per hour.
They’d be sh*tting kittens if they ever saw the costs they used to spend on prepping a VC10 ( and spare ) for a Royal.
I bet the Chileans at home are not kicking up a fuss over their 767 visiting Waddington