1) I am not sure anything *should* change.
2) The ADR is for a meal, not a PPO.
3) With any ADR that one wants to use as a PPO, one risks park hour changes.
4) And, sometimes park hour changes are made only 1-2 days ahead of time.
. . . actually, hour changes are very frequent
. . . CM's get "Advisories" on their computer screens all the time regarding park hour changes
5) Disney should not be responsible, as they are still providing the promised meal at the promised time.
6) Plus, there is no way of Disney to know why you scheduled such an early park ADR.
. . . it could be because you wanted to get in line somewhere
. . . it could be because you wanted a LONG and LIESURELY breakfast before touring
. . . it could be because you are slow eaters and want to take time to plan your day
NOTE: If Disney charged more for a meal that fell within a PPO time, then reverted to normal pricing after Rope Drop, I could see some kind of adjustment, but the prices are the same before and after Rope Drop, so the question is moot.