Found out more info about the Fastpass changes. It only affects the Multiple Experience FP's that are given out when an Attraction goes down.
Basically, each park has 2 "Groups" of Attractions.
When you have a FP for a Group 1 Attraction and it becomes "Temporarily Closed", you can use your Multiple Experience FP at any FP Attraction in that park.
But when you have a FP for a Group 2 Attraction and it becomes "Temporarily Closed", you can ONLY use your Multiple Experience FP at another Group 2 Attraction (NOT at a Group 1 Attraction)
Group 1 at DL is: Space Mountain, Indiana Jones Adventure, Matterhorn Bobsleds
Group 2 at DL: Everything else with FP
Group 1 at DCA is: Toy Story Midway Mania, Radiator Springs Racers
Group 2 at DCA: Everything else with FP