Short answer, yes.
I had a 1hr earlier change from a 2000 BNE-MEL to 1900 BNE-MEL. I pointed out i purposely booked 2000 as i needed that time to get BNE and was unlikely to make it by 1900.
Full (segment) refund (i still wanted the outbound leg) although domestic return effectively two one ways anyway.
I'd be arguing the reasons why it no longer works and if still told no then HUACA. It's worth pointing out 2.5hrs is significant time difference, whereas a 20min might be harder to argue.
It's helpful to "have a reason why the new time no longer works" (in your case presumably unable ot get to event at destination) and alternative options (eg. earlier in day flight) wont work for you.