The peak hours for spot prices aren't hard and fast. Generally think 7-9am, 5-7pm, but stuff happens. More a case of monitoring the price alerts from the app and mitigating usage when an extreme spike happens.
The default is flat rate lines charges in Kapiti, but if you can set things to run overnight/outside peak then I recommend changing your meter to support Smart Plan - Triple Saver. With this, the peak is 7-11am, 5-9pm, night is 11pm-7am, and inbetween is offpeak.
I understand they aren't exact, just having an indication helps.
So am I reading this right ? I would be a Standard user on the Smart Plan Option at the bottom of the page you linked ?
I have two meters to the house, they were updated 12 months ago I think.