No logic from your perspective, but from the details given I can't say which I would choose. Your original flight might have been at the earliest possible hour I would even consider traveling. (I'm a night owl.) When are the departure times relative to rush hour in your departure city? How can an automated system be built to pick what you (and every other SWA customer in every specific situation) would choose each and every time? In this primitive day and age (relative to 1,000 years hence), the answer is that it can't be done.