I think the difference will be if you have 8:25 ADR because that's all that was available or did you just request 8:25? If that was all that was available, they gave you that time because 8:00 was booked so you will have to wait to be seated. How long depends on how busy they are, but really what is the point of ADR's if you can show up anytime you want? I'm guessing since you came on here and asked instead of just calling and changing that you have already been told that 8:00 is booked.