tonyosborne,
Put simply and totally wrongly!
It's NOT for 14 aircraft, it's for total provision of the fleet and it's entire operation and support for 27 years. They are not airliners and will not be flying an airline operation when operated by the RAF so the comparison is meaningless. They are going to be fully certified military tanker transports.
Don't get me wrong, I think a PFI for this capability is a nonsense but we just do not have the cash up front now.