we changed dates for both our may and oct trips. our may saturday return flight left around 4pm, and cost almost $300. we wound up adding another day at the beginning of our vacation to at least get 10 days in, and changed to the friday night, for about half the price.
for oct, we are trying to add a night as the monday night departure is again very early and expensive.
it appears that we are going to have to book vacations based on what days SWA might have early outgoing, and late returning NS flights - hard to do with DVC 11 months in advance
a big "problem" is that we love,
love ISP. the airport itself is so clean, people are friendly, atmosphere (not security

) is relaxed, parking or drop-off is easy. if another airline started direct flights to MCO, we would switch from SWA without a moment's hesitation.