Hot water systems - Heat pump

Are there any heat pump experts out there? We installed a dux but the installer connected it to the continous supply not the off peak 1 our old electric storage hot water system used. Seems like a backward step to me going from off peak to continuous. Apparently dux states their heat pump systems can only be connected to the continous supply. Has anyone installed a heat pump hot water system and connected it to either off peak 1 or 2?