Save $80 and go home earlier? OH, my vacation time is worth at least $100 an hour (my exaggerated calculation!). So, an extra 4 hours in the park... I'd need to save at least $400.
Honestly, I'd pay the extra $80 and stay on vacation!!! In the grand scheme of things, $80 isn't a huge sum of money.
Think about how you'll feel getting off the plane. You'll probably be back at 2:30, just as your later flight would have been boarding. BUT, you would have had a few hours of quality park time.