Kei roto i te pūwero tīwiri e rua ngā wāhanga te whakamatao waenga i muri i te pūwerotanga tuatahi me te pūwerotanga tuarua, ka hua ake he tohatoha ōwehenga pūwero whaitake ake. Ka penapenahia e tēnei he 8%-15% te nui ake o te pūngao i ngā pūwerotanga kotahi-wāhanga, ka mau tonu te whakatauranga pai o te pūngao.
Ka whakaitihia te ōwehenga pēhanga o ia wāhanga e te pēhanga-rua-wāhanga, ka hua ake he pāmahana putanga iti iho, me te kawenga iti iho i runga i ngā peera pēhanga. Mā tēnei ka mau tonu te mahi pumau me te pono i ngā āhuatanga huarere katoa.