The rules that matter are the most generous of BA's as agent (basically vol refund for £35) or AA's as marketing airline for schedule change. As far as I can see, AA will give you the choice of a refund or rebooking in revenue bucket if the schedule change is 60 minutes or greater, so are those times quoted exactly: is it 60 minutes.

If the refund is available under AA terms, you might need to call or tweet AA to confirm this is the case.