DL is now flying SEA-FLL nonstop as well. I would definitely check the F fare on DL one way, if it is operating on your date.
The schedule sucks (redeye and not daily) but you can probably get 4 DL F tickets for the price of 2 on AS, get a full refund of your AS tickets, and possibly still get the vouchers or some other AS compensation (miles?). You can credit the miles to AS and probably earn at a similar rate to the AS F fare.