I would change it more often and the ester oil is NOT required by Nissan. If they tell you that, they're lying.
If you want to use something with ester in it, use Mobil 1. It's a whole lot cheaper than the over-priced snake oil that they're selling. The dealer's price of $120 is robbery. I did mine once and paid $92.
If you do want to use the Nissan oil, buy it online. Z1 Motorsports (site sponsor) has a kit for $59.99. Oil, filter and crush washer. You have to add shipping also. Cheaper if you buy multiples because the shipping gets cheaper per kit.
Nissan Oil Change Kit