auEstTime <- function(strdt) as.POSIXct(strdt, tz="Australia/Canberra")
auEstDeltaT <- function(t2, t1) { auEstTime(t2)-auEstTime(t1) }
# 2013-10-06 we'll loose one hour
auEstDeltaT('2013-10-06 06:00', '2013-10-06 00:00')
# Time difference of 5 hours # Right
auEstDeltaT('2013-10-06 03:00', '2013-10-06 02:00')
# Time difference of 2 hours # that's odd... beware edge case
auEstDeltaT('2013-10-06 03:00', '2013-10-06 01:59')
# Time difference of 1 mins # correct
auEstDeltaT('2013-10-06 02:59', '2013-10-06 02:00')
# Time difference of 0 secs  #edge case, so why not.
# 2013-04-07 we gained an hour 
auEstDeltaT('2013-04-07 03:00', '2013-04-07 02:00')
#Time difference of 2 hours
#For unknown reasons the behavior changes around minute 32 of that hour span.
auEstDeltaT('2013-04-07 03:00', '2013-04-07 02:32')
#Time difference of 1.466667 hours
auEstDeltaT('2013-04-07 03:00', '2013-04-07 02:33')
#Time difference of 27 mins