1: If he had an early delivery slot, he actually could have made money on this transaction. The original price on the green plane was I believe $58.5M or $59.5M but has since gone to over $70M in response to the demand and how far ahead available delivery slots are.
2: This is an early example in the production run, planes are always overweight early in the production run and improve over time. Maybe he was well informed about the marketed capabilities of the G650 but over-optimistic about what they'd be able to achieve by the time his delivery spot was reached. Maybe he wants to wait for a later model that will better conform to the marketed specs.
3: Shouldn't the G650, at its marketed specs, be able to get out with more range than any 7X or F900? 7000nm from a 5,900' field vs I believe ~5700nm from a 5600' field for the 7X. I don't see how there's any plane available that could leave any airfield with more range and passengers than the G650 as it is marketed.