I've never been open to the idea of awarding multiple victory conditions from different turns, and for plenty of reasons, but I'll just list the most basic scenario:
Obviously, the hypothetical game would be saved right before the spaceship launch and then played on to milk. The scores of the two .sav's would obviously be different, so I'd have to treat them as different games since Firaxis score determines some rankings and can be a tiebreaker in other rankings.
So then I have two games to vet, and there's two more problems. First, they'd both have the same mapseed, which puts one in violation of the map replay rule. Second, one of them would violate the reload rule (event change). Did the player manually launch the spaceship first and then reload to milk? Or did the player milk and then reload an earlier .sav to launch the spaceship?