Technically India has 1 hour + 15 overs. Last session will begin @ 2:30 and from 3:30 onwards Australia has to bowl 15 mandatory overs. So in addition to 15 mandatory overs, India will also get the number of overs which will be bowled in span of 1 hour(2:30 to 3:30) i.e almost 12 overs (in case all bowled by quickies)