You did say Nemo and Friends right? That would be the ride inside Epcot and would not include the Turtle Talk show which is FP separately and you're not talking about the Nemo show inside AK right?
If so, then I think moving up your FP is a good thing. You were never likely to have needed it anyway (if you don't believe me check the wait time for N&F at 6pm over the next few nights

), move the other FP you have up into that slot and let the first one expire unused and try to get a 4th FP for something that might actually be useful.